* arm-tdep.c (arm_find_mapping_symbol): New function, from

	* arm-tdep.c (arm_find_mapping_symbol): New function, from
	arm_pc_is_thumb.
	(arm_pc_is_thumb): Use arm_find_mapping_symbol.
	(extend_buffer_earlier): New function.
	(MAX_IT_BLOCK_PREFIX, IT_SCAN_THRESHOLD): New constants.
	(arm_adjust_breakpoint_address): New function.
	(arm_gdbarch_init): Register arm_adjust_breakpoint_address.

	testsuite/
	* gdb.arch/thumb2-it.S (it_breakpoints): New function.
	* gdb.arch/thumb2-it.exp (test_it_break): New function.
	(Top level): Call it.