[vector] RFR 8226918: Fix Vector API single jtreg failures for AArch64 NEON

[Yang Zhang (Arm Technology China)]

Hi

Could anyone please help to review this patch?

JBS: https://bugs.openjdk.java.net/browse/JDK-8226918
Webrev: http://cr.openjdk.java.net/~yzhang/vectorapi/8226918/webrev.00/

In float insert instructions, vRegF is low 32-bit of NEON register. Without TEMP_DEF, dst might use the same register with val. In such case, val may be overwritten by moving src to dst.
With this patch, single jtreg failures are fixed, and no new failure.

Regards,
Yang