RISC-V: Need to sync CPU features with related JVM flags

Currently, "features" string is not accurate in that the RISC-V CPU features/extensions which are disabled by user on the command are still added. We need to synchronize these features with related JVM flags so that "features" string can reflect actual usable CPU features.

1. "features" string without specifying any jvm flags

```
$ /home/zifeihan/jtreg/bin/jtreg -jdk:/home/zifeihan/jre/jdk /home/zifeihan/jdk/test/lib-test/jdk/test/whitebox/CPUInfoTest.java

----------System.out:(4/167)----------
WB.getCPUFeatures(): "rv64 i m a f d c v zba zbb zbs"
CPUInfo.getAdditionalCPUInfo(): ""
CPUInfo.getFeatures(): [rv64, i, m, a, f, d, c, v, zba, zbb, zbs]
TEST PASSED
```

2. "features" string with specifying `-XX:-UseZba`

```
$ /home/zifeihan/jtreg/bin/jtreg -javaoption:-XX:-UseZba -jdk:/home/zifeihan/jre/jdk /home/zifeihan/jdk/test/lib-test/jdk/test/whitebox/CPUInfoTest.java

----------System.out:(4/167)----------
WB.getCPUFeatures(): "rv64 i m a f d c v zba zbb zbs"
CPUInfo.getAdditionalCPUInfo(): ""
CPUInfo.getFeatures(): [rv64, i, m, a, f, d, c, v, zba, zbb, zbs]
TEST PASSED
```