simulate-thread.gdb: Use return value from simulate_thread_wrapper_other_threads

simulate-thread.gdb: Use return value from simulate_thread_wrapper_other_threads

	* gcc.dg/simulate-thread/simulate-thread.gdb: Use return value from
	simulate_thread_wrapper_other_threads
	* gcc.dg/simulate-thread/atomic-load-int128.c (simulate_thread_main):
	Move initialization of 'value' to main().
	(main): Initialize 'value';
	* gcc.dg/simulate-thread/speculative-store.c
	(simulate_thread_step_verify): Return 0 when successful.
	* gcc.dg/simulate-thread/simulate-thread.h (HOSTILE_THREAD_THRESHOLD):
	Reduce threshold.
	(INSN_COUNT_THRESHOLD): New.  Instruction limit to terminate test.
	(simulate_thread_wrapper_other_threads): Return a success/fail value
	and issue an error if the instruction count threshold is exceeded.

From-SVN: r184564