RFR: 8293285: x86_64: Move libm stub implementations to StubGenerator [v3]

[Vladimir Ivanov]

> Move libm stub implementations (used for trigonometric math intrinsics) from MacroAssembler to StubGenerator.
> 
> x86_32-specific code is left intact, but all `macroAssembler_x86_*.cpp` files are renamed to `macroAssembler_x86_32_*.cpp` since there's no x86_64-specific code left there anymore.
> 
> Testing: hs-tier1 - hs-tier4

Vladimir Ivanov has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains ten commits:

 - Merge branch 'master' into stub.x86_64.libm
 - Extract libm stub implementations into separate files
 - update
 - Merge branch 'master' into stub.x86_64.hpp
 - RuntimeStub
 - fix hs-minimal build
 - update
 - fix
 - stubGenerator_x86_64.hpp

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Changes: https://git.openjdk.org/jdk/pull/10133/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10133&range=02
  Stats: 23104 lines in 26 files changed: 11818 ins; 11257 del; 29 mod
  Patch: https://git.openjdk.org/jdk/pull/10133.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10133/head:pull/10133

PR: https://git.openjdk.org/jdk/pull/10133