RFR: 8356780: PhaseMacroExpand::_has_locks is unused [v2]

[Benoît Maillard]

> This PR introduces two cleanup changes to `PhaseMacroExpand`:
> 
> - Removes the unused field `PhaseMacroExpand::_has_locks`
> - Merges two `while` loops in `PhaseMacroExpand::eliminate_macro_nodes` into a single loop
> 
> Previously, `eliminate_macro_nodes` used two separate `while` loops:
> 
> - The first loop removed lock nodes
> - The second loop removed allocation nodes
> 
> Both loops had the same structure and independently traversed the same set of nodes. Since their operations do not interfere, the lock node removal logic was moved into the second loop as an additional case in the `switch` statement.
> 
> Thanks!

Benoît Maillard has updated the pull request incrementally with one additional commit since the last revision:

  8356780: Update copyright

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/25669/files
  - new: https://git.openjdk.org/jdk/pull/25669/files/4e7ee579..90c94a25

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25669&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25669&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/25669.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25669/head:pull/25669

PR: https://git.openjdk.org/jdk/pull/25669