More cleanups. Merging patterns with iterators, split out peepholes, etc.

More cleanups.  Merging patterns with iterators, split out peepholes, etc.

	* config/h8300/h8300.md (adds/subs splitters): Merge into single
	splitter.
	(negation expanders and patterns): Simplify and combine using
	iterators.
	(one_cmpl expanders and patterns): Likewise.
	(tablejump, indirect_jump patterns ): Likewise.
	(shift and rotate expanders and patterns): Likewise.
	(absolute value expander and pattern): Drop expander, rename pattern
	to just "abssf2"
	(peephole2 patterns): Move into...
	* config/h8300/peepholes.md: New file.