middle-end/114599 - fix bitmap allocation for check_ifunc_callee_symtab_nodes

middle-end/114599 - fix bitmap allocation for check_ifunc_callee_symtab_nodes

There's no default bitmap obstack during global CTORs, so allocate the
bitmap locally.

	PR middle-end/114599
	PR gcov-profile/114115
	* symtab.c (ifunc_ref_map): Do not use auto_bitmap.
	(is_caller_ifunc_resolver): Optimize bitmap_bit_p/bitmap_set_bit
	pair.
	(symtab_node::check_ifunc_callee_symtab_nodes): Properly
	allocate ifunc_ref_map here.

(cherry picked from commit 9ab8fdfeef5b1a47b358e08a98177b2fad65fed9)