RFR: 7903138: os.simpleArch is x64 for linux-riscv64 in @require context [v2]

[Feilong Jiang]

> Set simpleArch to riscv64 when os.arch is riscv64
> 
> Tested on  Linux riscv64. With the patch, [test/hotspot/jtreg/compiler/vectorapi/TestMaskedMacroLogicVector.java](https://github.com/openjdk/jdk/blob/jdk-19%2B13/test/hotspot/jtreg/compiler/vectorapi/TestMaskedMacroLogicVector.java) was successfully skipped.

Feilong Jiang has updated the pull request incrementally with one additional commit since the last revision:

  update comments

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

Changes:
  - all: https://git.openjdk.java.net/jtreg/pull/66/files
  - new: https://git.openjdk.java.net/jtreg/pull/66/files/6dc1206b..e589ae07

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jtreg&pr=66&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jtreg&pr=66&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jtreg/pull/66.diff
  Fetch: git fetch https://git.openjdk.java.net/jtreg pull/66/head:pull/66

PR: https://git.openjdk.java.net/jtreg/pull/66