x86: Check interrupt instead of noreturn attribute

ix86_set_func_type checks noreturn attribute to avoid incompatible
attribute error in LTO1 on interrupt functions.  Since TREE_THIS_VOLATILE
is set also for _Noreturn without noreturn attribute, check interrupt
attribute for interrupt functions instead.

gcc/

	PR target/114097
	* config/i386/i386-options.cc (ix86_set_func_type): Check
	interrupt instead of noreturn attribute.

gcc/testsuite/

	PR target/114097
	* gcc.target/i386/pr114097-1.c: New test.