[riscv-port-jdk11u:riscv-port] RFR: 8295110: RISC-V: Mark out relocations as incompressible

[Dingli Zhang]

Hi,
Please help review this backport to riscv-port-jdk11u.
This backport contains multiple issues:
- [8295110: RISC-V: Mark out relocations as incompressible](https://bugs.openjdk.org/browse/JDK-8295110)
- [8305112: RISC-V: Typo fix for RVC description](https://bugs.openjdk.org/browse/JDK-8305112)
- [8295396: RISC-V: Cleanup useless CompressibleRegions](https://bugs.openjdk.org/browse/JDK-8295396)
- [8305512: RISC-V: Enable RVC extension by default on](https://bugs.openjdk.org/browse/JDK-8305512)

The original patch cannot be directly applied because of riscv-port-jdk11u do not have ZGC andsome minor conflict resolution.
Another conflict is that we do not have the refactoring `8295270: RISC-V: Clean up and refactoring for assembler functions` on 11u.

It's also worth mentioning that there are some changes to the `8295110` implementation because jdk11u uses gnu++98 which cannot use lambda.

Testing:

- Tier1 passed without new failure on lp4a (release).

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

Commit messages:
 - 8305512: RISC-V: Enable RVC extension by default on
 - 8295396: RISC-V: Cleanup useless CompressibleRegions
 - 8305112: RISC-V: Typo fix for RVC description
 - 8295110: RISC-V: Mark out relocations as incompressible

Changes: https://git.openjdk.org/riscv-port-jdk11u/pull/45/files
  Webrev: https://webrevs.openjdk.org/?repo=riscv-port-jdk11u&pr=45&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295110
  Stats: 454 lines in 14 files changed: 235 ins; 73 del; 146 mod
  Patch: https://git.openjdk.org/riscv-port-jdk11u/pull/45.diff
  Fetch: git fetch https://git.openjdk.org/riscv-port-jdk11u.git pull/45/head:pull/45

PR: https://git.openjdk.org/riscv-port-jdk11u/pull/45