Revert "[TableGen] AsmMatcher: fix OpIdx computation when HasOptionalOperands is true"
Revert "[TableGen] AsmMatcher: fix OpIdx computation when HasOptionalOperands is true"

Breaks check-llvm under ubsan.

This reverts commit r309949.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@310008 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm