RFR: 8254158: Consolidate per-platform stack overflow handling code

[Coleen Phillimore]

Moved the duplicated code from posix based platform/cpu combinations into os_posix.cpp.  Left a little function to
determine frame at stack banging point for compiled methods (you can suggest a better name for it) to capture the
difference.

There are a bit of ifdefs but now there are less copies.

Tested with tier1-3 and stack overflow tests in vmTestbase/nsk/stress/stack on
linux-x86-debug,macosx-x86-debug,windows-x86-debug.  Built aarch64, arm32, ppc, s390, and zero.  Testing on these
platforms would be welcome.

Thanks,
Coleen

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Commit messages:
 - 8254158: Consolidate per-platform stack overflow handling code

Changes: https://git.openjdk.java.net/jdk/pull/620/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=620&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8254158
  Stats: 632 lines in 10 files changed: 119 ins; 464 del; 49 mod
  Patch: https://git.openjdk.java.net/jdk/pull/620.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/620/head:pull/620

PR: https://git.openjdk.java.net/jdk/pull/620