RFR: 8286669: Replace MethodHandle specialization with ASM in mainline [v5]

[Jorn Vernee]

> Hi,
> 
> This PR brings over commits from the panama-foreign repo. These commits mostly pertain to the switch to ASM and away from MethodHandle combinators for the binding recipe specialization. But, there is one more commit which adds freeing of downcall stubs, since those changes were mostly Java as well.
> 
> Thanks,
> Jorn
> 
> Testing: `run-test-jdk_foreign` with `-Dgenerator.sample.factor=-1` on Windows and Linux.

Jorn Vernee has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 118 commits:

 - Merge branch 'JEP-19-ASM' of https://github.com/JornVernee/jdk into JEP-19-ASM
 - Merge branch 'pr/7959' into JEP-19-ASM
 - Merge branch 'master' into JEP-19-VM-IMPL2
 - ifdef NOT_PRODUCT -> ifndef PRODUCT
 - Missing ASSERT -> NOT_PRODUCT
 - Cleanup UL usage
 - Fix failure with SPEC disabled (accidentally dropped change)
 - indentation
 - fix space
 - Merge branch 'master' into JEP-19-ASM
 - ... and 108 more: https://git.openjdk.java.net/jdk/compare/81e4bdbe...ce5c677a

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Changes: https://git.openjdk.java.net/jdk/pull/8685/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8685&range=04
  Stats: 2142 lines in 24 files changed: 1357 ins; 660 del; 125 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8685.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8685/head:pull/8685

PR: https://git.openjdk.java.net/jdk/pull/8685