Add builtin_elementwise_sin and builtin_elementwise_cos

Add codegen for llvm cos and sin elementwise builtins
The sin and cos elementwise builtins are necessary for HLSL codegen.
Tests were added to make sure that the expected errors are encountered
when these functions are given inputs of incompatible types.
The new builtins are restricted to floating point types only.

Reviewed By: craig.topper, fhahn

Differential Revision: https://reviews.llvm.org/D135011