[globalisel][tablegen] Fix a use-after free bug that manifests on non-macOS machines.
[globalisel][tablegen] Fix a use-after free bug that manifests on non-macOS machines.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@315765 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit c9676b5d356572b27936fb24d9d5f13688a7710a)

apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm