[PATCH][Power] Test vec_lvsl and vec_lvsr

This patch adds tests for vec_lvsl and vec_lvsr for all supported
data types.  This tests related changes to altivec.h that support
little endian code generation for these interfaces.



git-svn-id: https://llvm.org/svn/llvm-project/test-suite/trunk@219138 91177308-0d34-0410-b5e6-96231b3b80d8