[code-reflection] RFR: Address var name [v2]

[Mourad Abbay]

> Address var name

Mourad Abbay has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains six additional commits since the last revision:

 - Merge branch 'code-reflection' into var-name
 - Update TestVarOp following change in var.name for unnamed variables
 - Consider empty string as the value varName for unnamed variable
 - Apply suggestions
 - Add method CoreOp.VarOp.isUnnamedVariable
 - Update javadoc of CoreOp.var factory methods

-------------

Changes:
  - all: https://git.openjdk.org/babylon/pull/235/files
  - new: https://git.openjdk.org/babylon/pull/235/files/f8b95b70..fa15770d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=babylon&pr=235&range=01
 - incr: https://webrevs.openjdk.org/?repo=babylon&pr=235&range=00-01

  Stats: 4294 lines in 42 files changed: 3636 ins; 168 del; 490 mod
  Patch: https://git.openjdk.org/babylon/pull/235.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/235/head:pull/235

PR: https://git.openjdk.org/babylon/pull/235