Sema: Disable template instantiation once a fatal error is raised
Sema: Disable template instantiation once a fatal error is raised

Fatal errors disable all further diagnostics.  Continuing to permit
template instantiation does nothing but make it take longer for clang to
finish with the TU.

Instead, halt all further instantiation.

Fixed in PR22396.

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@227556 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang