RFR: 8266015: Implement AdapterHandlerLibrary lookup fast-path for common adapters [v4]

[Claes Redestad]

> This patch refactors AdapterHandlerLibrary initialization so that we can initialize a handful of commonly used adapters early during bootstrap, and avoid taking the AdapterHandlerLibrary_lock when looking up these adapters.
> 
> Since the 5 most common adapters plus the abstract adapter constitutes roughly 60% of the method shapes loaded and linked on a Hello World, this means a relatively significant startup optimization (~2M insns on Hello World); most of the win is in lookup code that will be a significant part of the cost of class loading even when no adapters need to be generated.
> 
> This enhancement partially recuperates the regression reported in https://bugs.openjdk.java.net/browse/JDK-8265523

Claes Redestad has updated the pull request incrementally with one additional commit since the last revision:

  Restructure initializer, reuse AdapterSignatureIterator in create_native_wrapper, minor improvements

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3706/files
  - new: https://git.openjdk.java.net/jdk/pull/3706/files/2bbb1198..2e299fc7

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3706&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3706&range=02-03

  Stats: 37 lines in 1 file changed: 10 ins; 21 del; 6 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3706.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3706/head:pull/3706

PR: https://git.openjdk.java.net/jdk/pull/3706