Vectors are not integer types, so the type system should not classify

Vectors are not integer types, so the type system should not classify
them as such. Type::is(Signed|Unsigned|)IntegerType() now return false
for vector types, and new functions
has(Signed|Unsigned|)IntegerRepresentation() cover integer types and
vector-of-integer types. This fixes a bunch of latent bugs.

Patch from Anton Yartsev!

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@109229 91177308-0d34-0410-b5e6-96231b3b80d8