Use `ImmutableList` where applicable

We're using List.of in many places in the code, this is inefficient as it could cause unnecessary copies when used in conjunction with ImmutableList as in ImmutableList.copyOf.
Here is a excerpt of a simple grep command that shows such instantiations:
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/provider/foundationdb/IndexingMerger.java:        return List.of(
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/cascades/PreOrderIterator.java:        stack.push(MutablePair.of(List.of(traversable.getThis()), INITIAL_POSITION));
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/cascades/expressions/GroupByExpression.java:                            List.of("AGG {{agg}}"),
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/cascades/expressions/GroupByExpression.java:                            List.of("AGG {{agg}}", "GROUP BY {{grouping}}"),
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/cascades/typing/Type.java:                Type wrapperType = Record.fromFields(List.of(Record.Field.of(new Array(elementType), Optional.of(NullableArrayTypeUtils.getRepeatedFieldName()))));
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/cascades/typing/Type.java:                Type wrapperType = Record.fromFields(List.of(Record.Field.of(new Array(elementType), Optional.of(NullableArrayTypeUtils.getRepeatedFieldName()))));
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/cascades/values/AndOrValue.java:                    List.of(Type.primitiveType(Type.TypeCode.BOOLEAN), Type.primitiveType(Type.TypeCode.BOOLEAN)),
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/cascades/values/InOpValue.java:                    List.of(new Type.Any(), new Type.Array()), (builtInFunc, args) -> encapsulateInternal(args));
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/cascades/values/JavaCallFunction.java:        super("java_call", List.of(Type.primitiveType(Type.TypeCode.STRING)), new Type.Any(), JavaCallFunction::findFunction);
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/cascades/values/RelOpValue.java:                    List.of(new Type.Any(), new Type.Any()), EqualsFn::encapsulate);
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/cascades/values/RelOpValue.java:                    List.of(new Type.Any(), new Type.Any()), NotEqualsFn::encapsulate);
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/cascades/values/RelOpValue.java:                    List.of(new Type.Any(), new Type.Any()), LtFn::encapsulate);
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/cascades/values/RelOpValue.java:                    List.of(new Type.Any(), new Type.Any()), LteFn::encapsulate);
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/cascades/values/RelOpValue.java:                    List.of(new Type.Any(), new Type.Any()), GtFn::encapsulate);
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/cascades/values/RelOpValue.java:                    List.of(new Type.Any(), new Type.Any()), GteFn::encapsulate);
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/cascades/values/RelOpValue.java:                    List.of(new Type.Any()), IsNullFn::encapsulate);
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/cascades/values/RelOpValue.java:                    List.of(new Type.Any()), NotNullFn::encapsulate);
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/cascades/values/UdfFunction.java:        super("", List.of(), (builtInFunction, arguments) -> null);
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/plans/RecordQueryComparatorPlan.java:                        List.of("COMPARE BY {{comparisonKey}}"),
fdb-record-layer-core/src/main/java/com/apple/foundationdb/record/query/plan/plans/RecordQuerySelectorPlan.java:                        List.of("SELECT BY {{planSelector}}"),
fdb-record-layer-core/src/test/java/com/apple/foundationdb/record/metadata/expressions/AbsoluteValueFunctionKeyExpression.java:            return List.of(Key.Evaluated.scalar(value), Key.Evaluated.scalar(-1L * value));
fdb-record-layer-core/src/test/java/com/apple/foundationdb/record/metadata/expressions/AbsoluteValueFunctionKeyExpression.java:            return List.of(new Builder());
fdb-record-layer-core/src/test/java/com/apple/foundationdb/record/metadata/expressions/IntWrappingFunction.java:            return List.of(new Builder());
fdb-record-layer-core/src/test/java/com/apple/foundationdb/record/provider/foundationdb/query/DualPlannerExtension.java:            this.extensions = List.of(setPlannerExtension(useCascadesPlanner));
fdb-record-layer-lucene/src/main/java/com/apple/foundationdb/record/lucene/LuceneScanSpellCheckParameters.java:            fields = List.of(fieldAndWord[0]);
fdb-record-layer-lucene/src/main/java/com/apple/foundationdb/record/lucene/directory/FieldInfosStorage.java:        wrappingDirectory.sync(List.of(fileName));
fdb-record-layer-lucene/src/main/java/com/apple/foundationdb/record/lucene/idformat/RecordIdFormat.java:            return new TupleElement(List.of(children));
FoundationDB / fdb-record-layer

Use `ImmutableList` where applicable #2483
