[LLParser] Remove unnecessary error check making sure NUW/NSW flags aren't set...

[LLParser] Remove unnecessary error check making sure NUW/NSW flags aren't set on a non-integer operation.

Summary: This check appears to be a leftover from when add/sub/mul could be either integer or fp. The NSW/NUW flags are only set for add/sub/mul/shl earlier. And we check that those operations only have integer types just below this. So it seems unnecessary to explicitly error for NUW/NSW being used on a add/sub/mul that have the wrong type that would later error for that.

Reviewers: spatel, dblaikie, jyknight, arsenm

Reviewed By: spatel

Subscribers: wdng, llvm-commits, hiraditya

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61562

llvm-svn: 359987