RFR(S) 8225018: 9 unit tests for Vector API failed on SkyLake with assert "(((dst_enc < 16 && nds_enc < 16 ..."

[Kharbas, Kishor]

Hi,

Requesting review for http://cr.openjdk.java.net/~kkharbas/vector-api/8225018/8225018.webrev.00/
Bug - https://bugs.openjdk.java.net/browse/JDK-8225018

Summary -

1.       Changed the instructs to take legacy registers when using vblendvps, vblendvpd, vpblendvb instructions. These instructions are not extended by AVX-512.

2.       Changed the order (unordered in some cases) so all instructs of same type are together.

Testing:
The failure can be reproduced consistently by forcing registers to be allocated from upper bank by limiting the lower bank registers. (by changing register class definitions).
After the fix, we do not see any more failures.

Thanks,
Kishor