x86: Support x32 and IBT in heap trampoline

x86: Support x32 and IBT in heap trampoline

Add x32 and IBT support to x86 heap trampoline implementation with a
testcase.

2024-02-13  Jakub Jelinek  <jakub@redhat.com>
	    H.J. Lu  <hjl.tools@gmail.com>

libgcc/

	PR target/113855
	* config/i386/heap-trampoline.c (trampoline_insns): Add IBT
	support and pad to the multiple of 4 bytes.  Use movabsq
	instead of movabs in comments.  Add -mx32 variant.

gcc/testsuite/

	PR target/113855
	* gcc.dg/heap-trampoline-1.c: New test.
	* lib/target-supports.exp (check_effective_target_heap_trampoline):
	New.