Fix use-after-free lexing unterminated raw strings (PR preprocessor/78811)

Fix use-after-free lexing unterminated raw strings (PR preprocessor/78811)

gcc/ChangeLog:
	PR preprocessor/78680
	PR preprocessor/78811
	* input.c (struct selftest::lexer_test): Add field
	m_implicitly_expect_EOF.
	(selftest::lexer_error_sink): New class.
	(selftest::lexer_error_sink::s_singleton): New global.
	(selftest::lexer_test::lexer_test): Initialize new field
	"m_implicitly_expect_EOF".
	(selftest::lexer_test::~lexer_test): Conditionalize the
	check for the EOF token on the new field.
	(selftest::test_lexer_string_locations_raw_string_unterminated):
	New function.
	(selftest::input_c_tests): Call the new test.

libcpp/ChangeLog:
	PR preprocessor/78680
	PR preprocessor/78811
	* lex.c (_cpp_lex_direct): Only determine the end-location of
	the token and build a range for non-reserved start locations.
	Do not do it for EOF tokens.

From-SVN: r243721