[AArch64] add tests for poor vector intrinsic lowering via legalization (PR38527); NFC

These correspond to the x86 tests added with rL339790 / rL339791, but I widened
the non-fsin tests to v3f32 to show the problem because AArch supports v2f32 ops. 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@339793 91177308-0d34-0410-b5e6-96231b3b80d8

Author: rotateright