Refactored code with different kinds of refactoring techniques

[NisargShah1410]

Applied different kinds of refactoring to multiple parts of code as below:

Extract method:

• Class : BTree
• Method : doGraftTempTree
• New method: mergeTryLeafNode.

Rename variable:

• Class : BTree

• Method : writeCachePrimer

• Line no. : 1365

• Variable : dout

• Class : BTreeValue

• Method : compactCheck

• Line no. : 108

• Variable : fLen

Introduce explaining variable :

• Class : BTreeValue

• Method : action

• Line no. : 376

• Variable : dout

• Class : BTreeValue

• Method : action

• Line no. : 380

• Variable : dout

Decompose conditional:

• Class : BTree
• Method : touch
• Line no. : 598

Move method:

• Class : BTree
• Method : redoStoreNullTxn

Replace conditional with polymorphism:

• Class : BTreeCursor
• Method : verifyFrames
• Line no. : 5220 [ switch case]

Push down method:

• Refactoring name : Push down method
• Package : src/main/java/org/cojen/tupl/repl ( org.cojen.tupl.core )
• Class : Replicator
• Method : newReader
• Line no. : 112

Extract class:

• Class : ServerCursor
• Method : readTransfer,writeTransfer
• Line no. : 351 to 403, 419 to 458

[broneill]

These changes don't appear to add value. It breaks code indenting, alters public API, renames variables for no particular reason, de-inlines code (with no improvement), adds unnecessary constants, moves code for no apparent reason, and increases code complexity.

This PR would be useful if it fixed bugs, added useful features, or improved documentation.