RFR: 8337791: VectorAPI jtreg ABSMaskedByteMaxVectorTests crashes with UseAVX=0 -XX:MaxVectorSize=8 [v2]

[Jatin Bhateja]

> This bug patch fixes a crash seen while querying the bottom type of MachTempNode corresponding to [rxmm0 operand](https://github.com/openjdk/jdk/blob/master/src/hotspot/cpu/x86/x86.ad#L22509) of blend pattern during late scheduling. Here, MaxVectorSize is contrainted to 8 bytes thus during C2 type system initialization, [TypeVect::VECTX ](https://github.com/openjdk/jdk/blob/master/src/hotspot/share/opto/type.cpp#L719) guarded by target supprted vector size remains uninitialized.
> 
> It better to reject matching of VectorBlend in such a scenario.
> 
> All exisitng VectorAPI jtreg tests are passing with -XX:UseAVX=0 and -XX:MaxVectorSize=8
> 
> Kindly review and share your feedback.
> 
> Best Regards,
> Jatin

Jatin Bhateja has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision:

  8337791: VectorAPI jtreg ABSMaskedByteMaxVectorTests crash with UseAVX=0 -XX:MaxVectorSize=8

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Changes:
  - all: https://git.openjdk.org/jdk/pull/28533/files
  - new: https://git.openjdk.org/jdk/pull/28533/files/70600498..6ca95427

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28533&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28533&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/28533.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28533/head:pull/28533

PR: https://git.openjdk.org/jdk/pull/28533