[LoopVectorizer] Add more testcases for PR33804.

Summary:
Add test cases when float <-> pointer types conversion is triggered
in presence of load instructions.

Reviewers: Ayal, srhines, mkuper, rengolin

Reviewed By: rengolin

Subscribers: javed.absar, llvm-commits

Differential Revision: https://reviews.llvm.org/D37967

llvm-svn: 313544