RFR: 8311130: AArch64: Sync SVE related CPU features with VM options [v2]

[Pengfei Li]

> As discussed in PR #14533, keeping AArch64 flag `UseSVE` and its related CPU features in sync helps to simplify rules in IR tests. In this patch, we mask SVE related CPU features off if specified SVE level in VM option is lower than the hardware supported. Also, to support this change, we move the features string construction to the end of the `initialize()` function.
> 
> We also revert IR rule changes in PR #14533 and fix some code styles. We tested almost full jtreg on SVE, SVE2 and non-SVE CPUs and no new issue is found after this patch.

Pengfei Li has updated the pull request incrementally with two additional commits since the last revision:

 - Simplify some checks
 - Address aph's comment

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Changes:
  - all: https://git.openjdk.org/jdk/pull/14897/files
  - new: https://git.openjdk.org/jdk/pull/14897/files/379fa9ce..85a3c05d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14897&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14897&range=00-01

  Stats: 21 lines in 8 files changed: 4 ins; 3 del; 14 mod
  Patch: https://git.openjdk.org/jdk/pull/14897.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14897/head:pull/14897

PR: https://git.openjdk.org/jdk/pull/14897