Avoid registering __builtin_setjmp_receiver label twice [PR101347]

Avoid registering __builtin_setjmp_receiver label twice [PR101347]

The testcase in the PR demonstrates how it is possible for one
__builtin_setjmp_receiver label to appear in
nonlocal_goto_handler_labels list twice (after the block with
__builtin_setjmp_setup referring to it was duplicated).

remove_node_from_insn_list did not account for this possibility and
removed only the first copy from the list. Add an assert verifying that
duplicates are not present.

To avoid adding a label to the list twice, move registration of the
label from __builtin_setjmp_setup handling to __builtin_setjmp_receiver.

gcc/ChangeLog:

	PR rtl-optimization/101347
	* builtins.cc (expand_builtin) [BUILT_IN_SETJMP_SETUP]: Move
	population of nonlocal_goto_handler_labels from here ...
	(expand_builtin) [BUILT_IN_SETJMP_RECEIVER]: ... to here.
	* rtlanal.cc (remove_node_from_insn_list): Verify that a
	duplicate is not present in the remainder of the list.