Minor GPU code cleanups
Add a conservative check that prevents alpha testing in a few cases.

This will become really powerful if we add some code to the vertex decoder
to check for non-full alpha in the vertices, and set gstate_c.vertexFullAlpha if none
is found (probably want to do the reverse, set it to true and clear if any non-255 alpha is found).

Alpha testing is a performance killer on many mobile GPUs so big efforts to
avoid it can be worth it.
Use vldmia not vld1 for QuickTexHashNEON().

It turns out this is ~20% slower usually, so aligned is not worth the
pipeline hit.
Minor improvements to QuickTexHashNEON().

Cuts a VFP switch, oops.
Don't use aligned loads in non-inlined funcs.

I'm wanting things to stay in registers, but that's not realistic for
arguments.  Force inline the others.  May help #5699.
Fix exists check in VFSFileSystem::GetFileInfo().

Only matters if it can't map the path / doesn't have the apk mapped (e.g.
as on headless right now.)
Properly fail loading state when fonts don't match.

It should fail later anyway, but this will prevent crashes just in case.
Add a NEON VMOV imm encoding to the emitter.
Support other constant VMOVs on NEON.

Float is especially useful.
Implement NEON register VMOVs.
Add a float->GP reg, fix VDUP for I_16.
Fix VLDM/VSTM encoding for D/Q regs.

Now it is actually using ASIMD/NEON.
vertexjit: Fix non-morph 5551 decoding.

Oops, it was just wrong before.
vertexjit: Save S16-S31 registers in ARM.
vertexjit: Support morph pos/norm on ARM as well.
vertexjit: support 8888 morph on ARM.
vertexjit: Attempt 16-bit color morphs on ARM.
vertexjit: Implement NEON color morphs on ARM.
vertexjit: Improve NEON align on color morph ARM.
vertexjit: Combine a few loads and stores on ARM.