RFR: 8321137: Reconsider ICStub alignment

[Aleksey Shipilev]

This continues from #16911. It initially started as performance optimization to compact `ICStubs`, but I think the safety arguments for fitting the `ICStub` per instruction cache line prevails. See bug and previous PR for more gory details. The footprint improvements on some architectures come as side-effect of untying the `ICStub` size from `CodeEntryAlignment` to (sometimes lower) cache line size.

Note that the size of `ICStub` is important, because `ICBuffer` is small (10K by default), and its depletion causes the `ICBufferFull` safepoint. I would make a (separate) argument to bump the default `ICBuffer` size a bit to make it less important.

Current patch affects `ICStub` size in different ways on different platforms, since current size is effectively 2x`CodeEntryAlignment` and new size is cache line size:
 - AArch64: 128 -> 64 bytes :)
 - x86_64: 64 -> 64 bytes :|
 - x86_32: 32 -> 64 bytes :(
 - PPC64: 512 -> 128 bytes :))
 - S390X: 128 -> 256 bytes :(
 - ARM: 32 -> 64 bytes :(
 - Zero: <not applicable, Zero does not use IC stubs>

Additional testing:
 - [x] Linux x86_64 server fastdebug, `tier{1,2,3,4}`
 - [x] Linux AArch64 server fastdebug, `tier{1,2,3,4}`

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Commit messages:
 - Work

Changes: https://git.openjdk.org/jdk/pull/17277/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17277&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8321137
  Stats: 66 lines in 6 files changed: 39 ins; 9 del; 18 mod
  Patch: https://git.openjdk.org/jdk/pull/17277.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17277/head:pull/17277

PR: https://git.openjdk.org/jdk/pull/17277