This patch fixes ICE on invalid code, specifically files that have
conflict-marker-like signs before EOF.

	PR c/92833
gcc/c/
	* c-parser.c (c_parser_consume_token): Fix peeked token stack pop
	to support 4 available tokens.

gcc/testsuite/
	* c-c++-common/pr92833-1.c, c-c++-common/pr92833-2.c,
	c-c++-common/pr92833-3.c, c-c++-common/pr92833-4.c: New tests.