RFR: 8332457: Examine startup overheads from JDK-8294961 [v12]

[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 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 13 additional commits since the last revision:

 - obsolete import
 - Merge branch 'master' into JDK-8332457-proxy-startup
 - missing bracket
 - Update src/java.base/share/classes/java/lang/reflect/ProxyGenerator.java
   
   Co-authored-by: liach <7806504+liach at users.noreply.github.com>
 - removed obsolete entry
 - MTD_ cleanup
 - fixed javadoc
 - CONDY implementation of ProxyGenerator
 - simplification of the proxy class loading
 - more improvements
 - ... and 3 more: https://git.openjdk.org/jdk/compare/386e173f...942342d5

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/19410/files
  - new: https://git.openjdk.org/jdk/pull/19410/files/24b60451..942342d5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19410&range=11
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19410&range=10-11

  Stats: 4440 lines in 143 files changed: 3169 ins; 738 del; 533 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