re PR sanitizer/81262 (verify_flow_info failed for asmgoto test-case with -fsanitize...

re PR sanitizer/81262 (verify_flow_info failed for asmgoto test-case with -fsanitize=undefined)

	PR sanitizer/81262
	* bb-reorder.c (fix_up_fall_thru_edges): Move variable declarations to
	the right scopes, make sure cond_jump isn't preserved between multiple
	iterations.  Search for fallthru edge whenever there are 3+ edges and
	use find_fallthru_edge for it.

	* gcc.c-torture/compile/pr81262.c: New test.
	* g++.dg/ubsan/pr81262.C: New test.

From-SVN: r249865