RFR: 8332457: Examine startup overheads from JDK-8294961 [v13]

[Adam Sotona]

> [JDK-8294961](https://bugs.openjdk.org/browse/JDK-8294961) changed to use classfile API for reflection proxy-generation. Actual implementation of `ProxyGenerator` is focused on performance, however it causes JDK bootstrap regressions. `ProxyGenerator.TEMPLATE` class model is statically created and each proxy class is transformed from the template.
> 
> This patch is intended to examine plain proxy generation impact on performance and JDK bootstrap (vs proxy transformation from template).
> 
> The generated proxy is migrated from static initialization to CONDY bootstrap.
> 
> Please review.
> 
> Thank you,
> Adam

Adam Sotona has updated the pull request incrementally with one additional commit since the last revision:

  added ProxyGenBench JMH micro benchmark

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Changes:
  - all: https://git.openjdk.org/jdk/pull/19410/files
  - new: https://git.openjdk.org/jdk/pull/19410/files/942342d5..834d65c5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19410&range=12
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19410&range=11-12

  Stats: 114 lines in 1 file changed: 114 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/19410.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19410/head:pull/19410

PR: https://git.openjdk.org/jdk/pull/19410