[SVE] Add more warnings checks to clang and LLVM SVE tests

There are now more SVE tests in LLVM and Clang that do not
emit warnings related to invalid use of EVT::getVectorNumElements()
and VectorType::getNumElements(). For these tests I have added
additional checks that there are no warnings in order to prevent
any future regressions.

Differential Revision: https://reviews.llvm.org/D82943