[TableGen] Cleanup output formatting and add llvm_unreachables to the output the AsmMatcher uses when it overflows the 64-bit tables. No in tree targets use this code, but I tested it with an temporarily reduced table width.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257583 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed