RFR: 8332900: RISC-V: refactor nativeInst_riscv.cpp and macroAssembler_riscv.cpp [v3]

[Hamlin Li]

> Hi,
> Can you help to review the patch?
> Currently, code in nativeInst_riscv.cpp and macroAssembler_riscv.cpp call each other, which is not right for readability and maintainance.
> After refactoring, basically only code in nativeInst_riscv.cpp calls code in macroAssembler_riscv.cpp, but not in reverse direction. The only exception is code related to `membar` where code in macroAssembler_riscv.cpp still calls code nativeInst_riscv.cpp, I'm not sure whether it should be refactored too.
> 
> Thanks!
> 
> * Tests are still running, so far so good.

Hamlin Li has updated the pull request incrementally with one additional commit since the last revision:

  restrict accessbility

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/19459/files
  - new: https://git.openjdk.org/jdk/pull/19459/files/cd408fe0..fe345dd3

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19459&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19459&range=01-02

  Stats: 77 lines in 1 file changed: 42 ins; 35 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/19459.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19459/head:pull/19459

PR: https://git.openjdk.org/jdk/pull/19459