x86: Replace ix86_red_zone_size with ix86_red_zone_used

Add red_zone_used to machine_function to track if red zone is used.
When expanding function prologue, set red_zone_used to true if red
zone is used.

gcc/

	PR target/101023
	* config/i386/i386.c (ix86_expand_prologue): Set red_zone_used
	to true if red zone is used.
	(ix86_output_indirect_jmp): Replace ix86_red_zone_size with
	ix86_red_zone_used.
	* config/i386/i386.h (machine_function): Add red_zone_used.
	(ix86_red_zone_size): Removed.
	(ix86_red_zone_used): New.
	* config/i386/i386.md (peephole2 patterns): Replace
	ix86_red_zone_size with ix86_red_zone_used.

gcc/testsuite/

	PR target/101023
	* g++.target/i386/pr101023a.C: New test.
	* g++.target/i386/pr101023b.C: Likewise.