RFR: 8301036: RISC-V: Factor out functions baseOffset & baseOffset32 from MacroAssembler [v2]

[Fei Yang]

> The functions baseOffset & baseOffset32 from MacroAssembler on RISC-V receive an Address in base_plus_offset mode. They check the range of the offset, add it and base and put the result in a destination register. This duplicates function MacroAssembler::la in functionality. We could refactor this part putting the logic of Address legitimization into MacroAssembler::la and use this function instead.
> 
> Testing:
>   - [x] Bootcycle (release & fastdebug)
>   - [x] Tier1-4 (release)
>   - [x] Benchmarks: SPECjbb2015 (release)

Fei Yang 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 three additional commits since the last revision:

 - Comment
 - Merge branch 'master' into JDK-8301036
 - 8301036: RISC-V: Factor out functions baseOffset & baseOffset32 from MacroAssembler

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/12177/files
  - new: https://git.openjdk.org/jdk/pull/12177/files/d1803d33..c617b7f8

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12177&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12177&range=00-01

  Stats: 9971 lines in 363 files changed: 3283 ins; 2129 del; 4559 mod
  Patch: https://git.openjdk.org/jdk/pull/12177.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12177/head:pull/12177

PR: https://git.openjdk.org/jdk/pull/12177