Don't manually (and forcibly) run the verifier on the entire module from

Don't manually (and forcibly) run the verifier on the entire module from
the jump instruction table pass. First, the verifier is already built
into all the tools. The test case is adapted to just run llvm-as
demonstrating that we still catch the broken module. Second, the
verifier is *extremely* slow. This was responsible for very significant
compile time regressions.

If you have deployed a Clang binary anywhere from r210280 to this
commit, you really want to re-deploy.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214287 91177308-0d34-0410-b5e6-96231b3b80d8