[vectorIntrinsics+mask] RFR: [X86] Masking support related cleanups.

[Jatin Bhateja]

- Some cleanups related to VectorLoadMask, VectorStoreMask and CICS patterns (one source is memory operand).

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

Commit messages:
 - [X86] Masking support related cleanups.

Changes: https://git.openjdk.java.net/panama-vector/pull/130/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=130&range=00
  Stats: 185 lines in 7 files changed: 20 ins; 73 del; 92 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/130.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/130/head:pull/130

PR: https://git.openjdk.java.net/panama-vector/pull/130