RFR: 8271078: jdk/incubator/vector/Float128VectorTests.java failed a subtest [v2]

[Dean Long]

> This test was failing because the safepoint polling stub was only saving the low 8 bytes of XMM16-XMM31.  We need to save all 16 bytes by default.  I also added "wide" to the boolean parameter name to better reflect what it controls.  And I made the asserts in save_live_registers() match what we have in restore_live_registers().

Dean Long has updated the pull request incrementally with one additional commit since the last revision:

  revert changes to asserts

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8690/files
  - new: https://git.openjdk.java.net/jdk/pull/8690/files/8709b627..e6a533a9

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8690&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8690&range=00-01

  Stats: 4 lines in 1 file changed: 1 ins; 1 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8690.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8690/head:pull/8690

PR: https://git.openjdk.java.net/jdk/pull/8690