[AArch64] Set TREE_TARGET_GLOBALS in aarch64_set_current_function when new tree is the default node to recalculate optab availability

	PR target/69245
	* config/aarch64/aarch64.c (aarch64_set_current_function):
	Save/restore target globals when switching to
	target_option_default_node.

	* gcc.target/aarch64/pr69245_1.c: New test.

From-SVN: r233745