Preserve inst-to-block and def-use in passes.

The following passes are updated to preserve the inst-to-block and
def-use analysies:

	private-to-local
	aggressive dead-code elimination
	dead branch elimination
	local-single-block elimination
	local-single-store elimination
	reduce load size
	compact ids (inst-to-block only)
	merge block
	dead-insert elimination
	ccp

The one execption is that compact ids still kills the def-use manager.
This is because it changes so many ids it is faster to kill and rebuild.

Does everything in
https://github.com/KhronosGroup/SPIRV-Tools/issues/1593 except for the
changes to merge return.