[riscv-port-jdk11u:riscv-port] RFR: 8314420: Initial patch of JDK11u riscv port

[kuaiwei]

It's the initial patch based on https://github.com/openjdk/jdk17u-dev/pull/1427 , and revert patches not required in JDK11u. The testing is running on a linux riscv board. There are some failed cases and we are working on fix them , the progress will updated.

Thanks the contribution of OpenJDK community and hard working of @zhengxiaolinX .

- [x]  slowdebug/fastdebug/release build
- [x] Benchmark: SPECJbb2015, Renaissance
- [ ]  Tier1 tests
- [ ] Tier2 tests
- [ ] Tier3 tests
- [ ] Tier4 tests

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

Commit messages:
 - Save all call-clobbered registers for spark tests may crash
 - Misc adaptations to jdk11u
 - Revert JDK-8213436: Obsolete UseMembar && JDK-8188764: Obsolete AssumeMP and then remove all support for non-MP builds, always enabled
 - Revert:
 - Revert JDK-8220049: Obsolete ThreadLocalHandshakes
 - Revert JDK-8272873: C2: Inlining should not depend on absolute call site counts
 - Revert JDK-8220051: Remove global safepoint code
 - Revert JDK-8222637: Obsolete NeedsDeoptSuspend
 - Revert:
 - Revert JDK-8230392: Define AArch64 as MULTI_COPY_ATOMIC
 - ... and 118 more: https://git.openjdk.org/riscv-port-jdk11u/compare/8907d7d0...64c2e893

Changes: https://git.openjdk.org/riscv-port-jdk11u/pull/3/files
 Webrev: https://webrevs.openjdk.org/?repo=riscv-port-jdk11u&pr=3&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8314420
  Stats: 54933 lines in 177 files changed: 54741 ins; 68 del; 124 mod
  Patch: https://git.openjdk.org/riscv-port-jdk11u/pull/3.diff
  Fetch: git fetch https://git.openjdk.org/riscv-port-jdk11u.git pull/3/head:pull/3

PR: https://git.openjdk.org/riscv-port-jdk11u/pull/3