PR c/110699: Defend against error_mark_node in gimplify.cc.

PR c/110699: Defend against error_mark_node in gimplify.cc.

This patch resolves PR c/110669, an ICE-after-error regression, by adding
a check that the array type isn't error_mark_node in gimplify_compound_lval.

2023-07-21  Roger Sayle  <roger@nextmovesoftware.com>
	    Richard Biener  <rguenther@suse.de>

gcc/ChangeLog
	PR c/110699
	* gimplify.cc (gimplify_compound_lval):  If the array's type
	is error_mark_node then return GS_ERROR.

gcc/testsuite/ChangeLog
	PR c/110699
	* gcc.dg/pr110699.c: New test case.