testsuite/52641: Fix fallout from sloppy tests.

gcc/testsuite/
	PR testsuite/52641
	* gcc.dg/torture/pr110838.c: Use proper shift offset to get MSB or int.
	* gcc.dg/torture/pr112282.c: Use at least 32 bits for :20 bit-fields.
	* gcc.dg/tree-ssa/bitcmp-5.c: Use integral type with 32 bits or more.
	* gcc.dg/tree-ssa/bitcmp-6.c: Same.
	* gcc.dg/tree-ssa/cltz-complement-max.c: Same.
	* gcc.dg/tree-ssa/cltz-max.c: Same.
	* gcc.dg/tree-ssa/if-to-switch-8.c: Use literals that fit int.
	* gcc.dg/tree-ssa/if-to-switch-9.c [avr]: Set case-values-threshold=3.
	* gcc.dg/tree-ssa/negneg-3.c: Discriminate [not] large_double.
	* gcc.dg/tree-ssa/phi-opt-25b.c: Use types of correct widths for
	__builtin_bswapN.
	* gcc.dg/tree-ssa/pr55177-1.c: Same.
	* gcc.dg/tree-ssa/popcount-max.c: Use int32_t where required.
	* gcc.dg/tree-ssa/pr111583-1.c: Use intptr_t as needed.
	* gcc.dg/tree-ssa/pr111583-2.c: Same.