Rename test pr30298.ll to shrink_vmul_sse.ll, to make the name more meaningful, NFC.

Add PR number and comment in pr30298.ll to explain what is testing.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280843 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed