[riscv-port] RFR: 8277431: riscv: Intrinsify recursive ObjectMonitor locking for C2

[Yadong Wang]

According to https://bugs.openjdk.java.net/browse/JDK-8277180, the C2 fast_lock and fast_unlock intrinsics don't support recursive ObjectMonitor locking. Some workload can significantly benefit from this. This fixes the problem on riscv.
Tier1 tests of hotspot and jdk are passed on unmatched and all JTreg tests are tested on qemu without new failures.

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Commit messages:
 - 8277431: riscv: Intrinsify recursive ObjectMonitor locking for C2

Changes: https://git.openjdk.java.net/riscv-port/pull/13/files
 Webrev: https://webrevs.openjdk.java.net/?repo=riscv-port&pr=13&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8277431
  Stats: 21 lines in 1 file changed: 20 ins; 1 del; 0 mod
  Patch: https://git.openjdk.java.net/riscv-port/pull/13.diff
  Fetch: git fetch https://git.openjdk.java.net/riscv-port pull/13/head:pull/13

PR: https://git.openjdk.java.net/riscv-port/pull/13