StripDebugInfo: uses isa<DbgInfoIntrinsic> instead of matching against llvm.dbg.* (NFC)

Suggested by Adrian. This is NFC right now but is more clean and
robust against future potential new debug info intrinsics.

From: mehdi_amini <mehdi_amini@91177308-0d34-0410-b5e6-96231b3b80d8>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269540 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed