[riscv-port] RFR: 8282415: riscv: Rename StubRoutines::riscv64 to StubRoutines::riscv [v2]

[Feilong Jiang]

> Rename `SubRoutine::riscv64` to `SubRoutine::riscv`, just like the PPC64 port.
> 
> Tier1 tests on QEMU are passed without new faliures.

Feilong Jiang has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

 - Merge branch 'riscv-port' of https://github.com/openjdk/riscv-port into rename
 - 8282415: riscv: Rename StubRoutines::riscv64 to StubRoutines::riscv

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

Changes:
  - all: https://git.openjdk.java.net/riscv-port/pull/60/files
  - new: https://git.openjdk.java.net/riscv-port/pull/60/files/11d64a0a..d138f72d

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=riscv-port&pr=60&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=riscv-port&pr=60&range=00-01

  Stats: 2697 lines in 67 files changed: 2118 ins; 342 del; 237 mod
  Patch: https://git.openjdk.java.net/riscv-port/pull/60.diff
  Fetch: git fetch https://git.openjdk.java.net/riscv-port pull/60/head:pull/60

PR: https://git.openjdk.java.net/riscv-port/pull/60