RFR: 8332457: Examine startup overheads from JDK-8294961

[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).

Please review.

Thank you,
Adam

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Commit messages:
 - 8332457: Examine startup overheads from JDK-8294961

Changes: https://git.openjdk.org/jdk/pull/19410/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19410&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8332457
  Stats: 233 lines in 1 file changed: 27 ins; 113 del; 93 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