[riscv-port-jdk17u:riscv-port] RFR: 8276799: Implementation of JEP 422: Linux/RISC-V Port [v2]

[Yadong Wang]

> This PR backports the implementation of RISC-V port into jdk17u. 
> 
> It based on the initial implementation of JEP-422 with some modifications for jdk17u:
> 1.	The initial patch
>     8276799: Implementation of JEP 422: Linux/RISC-V Port
> 2.	 remove features that do not belong to jdk17u
>     revert 8277417: C1 LIR instruction for load-klass
>     revert 8278387: Implement UseHeavyMonitors consistently
>     revert 8227369: pd_disjoint_words_atomic() needs to be atomic
>     revert 8258192: Obsolete the CriticalNatives flag
>     revert 8281632: riscv: Improve interpreter stack banging
>     revert 8283364: Intrinsify countPositives
> 3.	add features that belongs to jdk17u
>     enable the biased locking
> 4.	 Wrap modifications to shared code under RISCV and revert changes to other platforms
> isolate modification to other platforms
> 5.	Patches for making compilation pass
> 8282306: os::is_first_C_frame(frame*) crashes on invalid link access
> 8282477: vmassert(_last_Java_pc == NULL, "already walkable"); fails with async profiler

Yadong Wang has updated the pull request incrementally with one additional commit since the last revision:

  fix indentation

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

Changes:
  - all: https://git.openjdk.org/riscv-port-jdk17u/pull/1/files
  - new: https://git.openjdk.org/riscv-port-jdk17u/pull/1/files/47916a22..f59f403f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=riscv-port-jdk17u&pr=1&range=01
 - incr: https://webrevs.openjdk.org/?repo=riscv-port-jdk17u&pr=1&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/riscv-port-jdk17u/pull/1.diff
  Fetch: git fetch https://git.openjdk.org/riscv-port-jdk17u pull/1/head:pull/1

PR: https://git.openjdk.org/riscv-port-jdk17u/pull/1