[code-reflection] RFR: Remove the code model transformation: addVarsWhenNecessary. [v5]

[Mourad Abbay]

> We remove the code model transformation: `addVarsWhenNecessary`.

Mourad Abbay has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains nine commits:

 - Remove unnecessary comments
 - Merge branch 'code-reflection' into remove-addVarsWhenNecessary
   
   # Conflicts:
   #	src/jdk.incubator.code/share/classes/jdk/incubator/code/internal/CodeModelToAST.java
 - Map Value to VarSymbol
 - Simplify CodeModelToAST.exprTree
 - Refactor.
 - All InvokeOps (we can have) can be me mapped to JCExpression directly.
 - The mapping of returnValue to tree is not going to be requested, so no need to store it.
 - Map ArrayStoreOp to a JCExpression.
 - Remove the code model transformation: addVarsWhenNecessary.

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Changes: https://git.openjdk.org/babylon/pull/387/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=387&range=04
  Stats: 100 lines in 1 file changed: 25 ins; 63 del; 12 mod
  Patch: https://git.openjdk.org/babylon/pull/387.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/387/head:pull/387

PR: https://git.openjdk.org/babylon/pull/387