For integer constants, allow 'L', 'UL' as well as 'ULL' and 'LL'. This provides
better support for shared headers between .s and .c files that define bunches
of constant values.
rdar://9321056
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176118 91177308-0d34-0410-b5e6-96231b3b80d8