RFR: 8318222: RISC-V: C2 CmpU3

[Hamlin Li]

Hi,
Can you review the change to add intrinsic for CmpU3 and CmpUL3?
Thanks!

## Test

### functionality
pass jtreg test:
jdk/java/lang/Long/Unsigned.java, jdk/java/lang/Integer/Unsigned.java

### performance
#### Long
**before**:
Benchmark                      (size)  Mode  Cnt       Score       Error  Units
Longs.compareUnsignedDirect       500  avgt    5    1454.789 ±   129.557  ns/op
Longs.compareUnsignedIndirect     500  avgt    5    1410.146 ±   120.017  ns/op

**after**:
Benchmark                      (size)  Mode  Cnt       Score       Error  Units
Longs.compareUnsignedDirect       500  avgt    5    1286.129 ±     8.441  ns/op
Longs.compareUnsignedIndirect     500  avgt    5     993.490 ±     0.840  ns/op

#### Integer
**before**:
Benchmark                         (size)  Mode  Cnt       Score       Error  Units
Integers.compareUnsignedDirect       500  avgt    5    1611.753 ±     0.700  ns/op
Integers.compareUnsignedIndirect     500  avgt    5    1775.093 ±     1.520  ns/op

**after**:
Benchmark                         (size)  Mode  Cnt       Score       Error  Units
Integers.compareUnsignedDirect       500  avgt    5    1159.351 ±     0.601  ns/op
Integers.compareUnsignedIndirect     500  avgt    5     776.185 ±     0.924  ns/op

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

Commit messages:
 - indent
 - rename from 'ui' to 'uw'
 - Merge branch 'master' into compareUnsigned
 - fix indent
 - Initial commit

Changes: https://git.openjdk.org/jdk/pull/16314/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16314&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8318222
  Stats: 67 lines in 3 files changed: 63 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/16314.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16314/head:pull/16314

PR: https://git.openjdk.org/jdk/pull/16314