[RewriteStatepointsForGC] Cleanup - replace std::vector usage [NFC]

Migrate std::vector usage to a combination of SmallVector and ArrayRef.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230079 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed