RFR: 8305056: Avoid unaligned access in emit_intX methods if it's unsupported [v7]

[Vladimir Kempik]

> Please review this change which attempts to eliminate unaligned memory stores generated by emit_int16/32/64 methods on some platforms.
> 
> Primary aim is risc-v platform. But I had to change some code in ppc/arm32/x86 to prevent possible perf degradation.

Vladimir Kempik has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 10 additional commits since the last revision:

 - Merge
 - Rewrite few more helpers
 - Add APH's suggestions and remove some whitespace
 - Rework the fix to use memcpy in codeBuffer.hpp
 - Reduce code duplication
 - Fix 32-bit archs
 - Fix typo
 - change long to ulong in type convertion
 - Fix includes
 - 8305056: Avoid unaligned access in emit_intX methods if not enabled

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/13227/files
  - new: https://git.openjdk.org/jdk/pull/13227/files/81861821..b221242a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13227&range=06
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13227&range=05-06

  Stats: 275367 lines in 2564 files changed: 238622 ins; 22050 del; 14695 mod
  Patch: https://git.openjdk.org/jdk/pull/13227.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13227/head:pull/13227

PR: https://git.openjdk.org/jdk/pull/13227