RFR: 8357728: Optimize Executable#synthesizeAllParams [v2]

[Chen Liang]

> Currently, fake parameters are created with "arg0" etc. strings that are retained for class file methods with no MethodParameters attribute. The original issue report observes many of these strings present in the heap. To address this issue, we can remove these eagerly created fake names, bringing their behavior in line with nameless parameters from MethodParameters attribute, such as those from inner class constructors. A unit test verifies that no name is retained in the Parameter object when the name is fake.
> 
> The original report recommends using a pool to store the arg name strings. I did not take that approach as I don't think it is very necessary; if the issue of retained fake names persist, we can update `Parameter::getName` to return fake names from a pool instead.

Chen Liang 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 two additional commits since the last revision:

 - Merge branch 'master' of https://github.com/openjdk/jdk into fix/fake-param-name
 - 8357728: Optimize Executable#synthesizeAllParams

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Changes:
  - all: https://git.openjdk.org/jdk/pull/25961/files
  - new: https://git.openjdk.org/jdk/pull/25961/files/a5a5dba4..a79e59cd

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25961&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25961&range=00-01

  Stats: 607435 lines in 7235 files changed: 409421 ins; 125072 del; 72942 mod
  Patch: https://git.openjdk.org/jdk/pull/25961.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25961/head:pull/25961

PR: https://git.openjdk.org/jdk/pull/25961