Avoid direct casting primitive core instances

This PR proposes a change to avoid direct casting primitive core instances during interpreted flow to better interoperate with compile primitives ValCoreInstance. By delegating to the primitive class, we can either direct cast or create a new instance to meet the expected type.

This is important for the legend-engine compile function, as interpreted flow interoperate with compiled instances. Without this change, the code ends on class cast exception like this:

Caused by: java.lang.ClassCastException: class org.finos.legend.pure.runtime.java.compiled.generation.processors.support.coreinstance.ValCoreInstance cannot be cast to class org.finos.legend.pure.m4.coreinstance.primitive.StringCoreInstance (org.finos.legend.pure.runtime.java.compiled.generation.processors.support.coreinstance.ValCoreInstance and org.finos.legend.pure.m4.coreinstance.primitive.StringCoreInstance are in unnamed module of loader 'app')
    at org.finos.legend.pure.m3.coreinstance.meta.pure.metamodel.function.ConcreteFunctionDefinitionInstance.addKeyValue(ConcreteFunctionDefinitionInstance.java:1012)
    at org.finos.legend.pure.m3.navigation.Instance.addValueToProperty(Instance.java:90)
    at org.finos.legend.pure.runtime.java.interpreted.natives.grammar.lang.Copy.copy(Copy.java:204)
    at org.finos.legend.pure.runtime.java.interpreted.natives.grammar.lang.Copy.execute(Copy.java:165)
    at org.finos.legend.pure.runtime.java.interpreted.FunctionExecutionInterpreted.executeFunction(FunctionExecutionInterpreted.java:486)
    ... 34 more

finos / legend-pure

Avoid direct casting primitive core instances #678

Test Results