Refactor sparse resources module

Refactor sparse resources module

Get rid of unused functions and custom classes where common
framework-provided utilities suffice.

Affected tests:
- dEQP-VK.sparse_resources.shader_intrinsics.*_sparse_sample_explicit_lod.*
- dEQP-VK.sparse_resources.shader_intrinsics.*_sparse_sample_implicit_lod.*
- dEQP-VK.sparse_resources.shader_intrinsics.*_sparse_gather.*
- dEQP-VK.sparse_resources.* (only code changed)

Sparse sample tests now use a different graphics pipeline, but their
behavior should remain unchanged.

Change-Id: Ib3b5158f142630360c1b5e176f16b2f604de8dfe