RFR: 8282432: Optimize masked "test" Vector API with predicate feature [v2]

[Xiaohong Gong]

> The vector `"test"` api is implemented with vector `"compare"`. And the masked `"test" `is implemented with `"test(op).and(m)"` which means `"compare().and(m)"` finally. Since the masked vector `"compare"` has been optimized with predicated instruction for archituctures that support the feature, the masked `"test"` can also be optimized by implementing it with the predicated compare. This could save the additional ` "and"` for architectures that support the predicate feature.
> 
> This patch optimized the masked `"test"` by implementing it with masked `"compare"`. With this patch, the following codes for the` "IS_NEGATIVE"` op for a DoubleVector with SVE:
> 
>   mov z19.d, #0
>   cmpgt   p1.d, p7/z, z19.d, z17.d
>   and p0.b, p7/z, p1.b, p0.b
> 
> are optimized to:
> 
>   mov z19.d, #0
>   cmpgt   p0.d, p0/z, z19.d, z17.d
> 
> Also update the jtreg tests for masked` "test" ` to make sure they are hot enough to be compiled by c2.

Xiaohong Gong has updated the pull request incrementally with one additional commit since the last revision:

  Simply the testTemplate

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7654/files
  - new: https://git.openjdk.java.net/jdk/pull/7654/files/41a9d56f..c90d2f49

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7654&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7654&range=00-01

  Stats: 197 lines in 49 files changed: 13 ins; 33 del; 151 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7654.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7654/head:pull/7654

PR: https://git.openjdk.java.net/jdk/pull/7654