Fix for issue 1351 - Analyzer accepts non-multiline strings with newlines

tests/language/language.status

 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 # This directory contains tests that are intended to show the
 # current state of the language.
 
 # In order to maintain maximum test coverage for all builds,
 # please use the following procedure to mark a test
 # failed on architectures other than the one you are working on.
@@ skipping 87 matching lines @@
 pseudo_kw_illegal_test/08: Fail # Issue 356
 pseudo_kw_illegal_test/10: Fail # Issue 356
 pseudo_kw_illegal_test/14: Fail # Issue 356
 pseudo_kw_test: Fail           # Issue 356
 scope_negative_test: Fail      # Bug 4207538.
 static_call_wrong_argument_count_negative_test: Fail
 static_field1_run_negative_test: Fail  # issue 1662
 static_field1a_run_negative_test: Fail # issue 1662
 static_field2_run_negative_test: Fail  # issue 1662
 static_field2a_run_negative_test: Fail # issue 1662
-string_escape1_negative_test: Fail # Issue 1351.
-string_escape4_negative_test: Fail # Issue 1351.
 string_interpolation8_test: Fail # Issue 2126.
 switch3_negative_test: Fail # issue 1663
 switch7_negative_test: Fail    # Bug 4208467.
 switch_label_test: Fail        # Bug 4208467.
 syntax_test: Skip             # Bug 2107  Static type warnings in none case
 third_test: Skip # Seems flaky in dartc after fixing test, was Bug 5339586
 throw7_negative_test: Fail     # Bug 4208459.
 type_dartc_test: Fail          # Issue 2348
 type_variable_bounds_test/00: Fail # issue 3079
 constructor_redirect_test/01: Fail # For the wrong reason - Issue 2105.
@@ skipping 306 matching lines @@
 constructor_redirect2_negative_test: Skip # Undiagnosed infinite loop.
 
 [ $compiler == frog && $runtime == none ]
 *: Skip
 
 [ $arch == simarm ]
 *: Skip
 
 [ $arch == arm ]
 *: Skip