[mlir][SerializeToHsaco] Minimize dependencies of AMDGPU compilation

The SerializeToHsaco uses functions from ExecutionEngineUtils to set
up LLVM pass pipelines, but does not otherwise depend on the execution
engine (except indirectly via a dependency on IPO). This commit
removes the dependency on the execution engine to prevent
unnecessarily compilations.

Reviewed By: ThomasRaoux

Differential Revision: https://reviews.llvm.org/D138041