citra-qt: static-constify a map.
Pica/DebugUtils: Make a number of variables static.

Makes for cleaner and faster code.
Pica/Rasterizer: Get rid of C-style casts.
Pica/Rasterizer: Build fix.
Pica/DebugUtils: Better document LookupTexture.
Pica: Implement operators == and != in float24 less lazily.
Pica/DebugUtils: Fix two warnings.
Pica/PrimitiveAssembly: Remove two useless log messages.
Revert "Pica/DebugUtils: Factor out BreakPointObserverDock into its own file."

This reverts commit 06893217630ed3ec1b882ede61d472bffda67626.

This commit was not meant to be included in this branch.
Revert "Revert "Pica/DebugUtils: Factor out BreakPointObserverDock into its own file.""

This reverts commit 4c906688d08d87ae1f3c0d96f857eb4e28ca377f.

Reintroduce this for my local stuff.
Pica/CommandProcessor: Remove an unnecessary log message.
Pica/DebugUtils: Further cleanups to LookupTexture.
Pica/Rasterizer: Fix a critical regression.
Pica/VertexShader: Small clean up
Pica/VertexShader: Clarify a comment.
Pica/VertexShader: Be robust against invalid inputs.

More specifically, this also fixes crashes by Citra trying to load a src2 register even if the current instruction does not use that.
Pica/DebugUtils: Fix a crash in the texture viewing widget.