[ARC] Fix LE tests for nps400 variant.

gcc/arc: New peephole2 and little endian arc test fixes

Resolve some test failures introduced for little endian arc as a result
of the recent arc/nps400 additions.

There's a new peephole2 optimisation to merge together two zero_extracts
in order that the movb instruction can be used.

One of the test cases is extended so that the test does something
meaningful in both big and little endian arc mode.

Other tests have their expected results updated to reflect improvements
in other areas of GCC.

gcc/ChangeLog:

 Andrew Burgess  <andrew.burgess@embecosm.com>

	* config/arc/arc.md (movb peephole2): New peephole2 to merge two
	zero_extract operations to allow a movb to occur.
	* gcc.target/arc/movb-1.c: Update little endian arc results.
	* gcc.target/arc/movb-2.c: Likewise.
	* gcc.target/arc/movb-5.c: Likewise.
	* gcc.target/arc/movh_cl-1.c: Extend test to cover little endian
	arc.

From-SVN: r242484