[spirv] Add conv CodeGen configuration for Adreno GPUs (#7001)

Similar to matmul, this enables tiling and vectorizing conv ops for
Adreno GPUs.

The goal is to eventually promote what's here as the default for all
targets, including Mali GPUs, so that we can remove the hardcoded
known good configurations. But for now starting with Adreno to
make sure they work fine.

Along the way, moved the "fourth-level" tiling into the pattern itself.
It's really fundamentally different than the others. We don't have
four levels of compute hierarchies on GPU to map to. We just used
it as a way to materialize the loops around filter height and width.
It's required for applicability and correctness for the pattern
itself and is always the same, not tunable knobs that change
according to the input.