i386: Use generic division to generate INVALID and DIVZERO exceptions

i386: Use generic division to generate INVALID and DIVZERO exceptions

Introduce math_force_eval to evaluate generic division to generate
INVALID and DIVZERO exceptions.

libgcc/ChangeLog:

	* config/i386/sfp-exceptions.c (__math_force_eval): New define.
	(__sfp_handle_exceptions): Use __math_force_eval to evaluete
	generic division to generate INVALID and DIVZERO exceptions.

libatomic/ChangeLog:

	* config/x86/fenv.c (__math_force_eval): New define.
	(__atomic_feraiseexcept): Use __math_force_eval to evaluete
	generic division to generate INVALID and DIVZERO exceptions.

libgfortran/ChangeLog:

	* config/fpu-387.h (__math_force_eval): New define.
	(local_feraiseexcept): Use __math_force_eval to evaluete
	generic division to generate INVALID and DIVZERO exceptions.