Fix the return type of String.split in DDC to be correct

tests/corelib_2/corelib_2.status

 # Copyright (c) 2017, 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.
 
 # All static_tests have expected compile-time errors.
 [ $strong && $compiler != dart2analyzer && $compiler != dartdevc ]
 core_runtime_types_static_test: MissingCompileTimeError
 splay_tree_test/01: MissingCompileTimeError
 splay_tree_test/02: MissingCompileTimeError
 string_base_vm_static_test: MissingCompileTimeError
@@ skipping 162 matching lines @@
 int_modulo_arith_test/modPow: RuntimeError # Issue 29921
 regress_r21715_test: RuntimeError # Requires bigint support.
 int_parse_with_limited_ints_test: Skip # dart2js and dartdevc don't know about --limit-ints-to-64-bits
 typed_data_with_limited_ints_test: Skip # dart2js and dartdevc don't know about --limit-ints-to-64-bits
 
 [ $compiler == dart2js && $runtime != none ]
 nan_infinity_test/01: RuntimeError
 integer_to_string_test/01: RuntimeError
 iterable_to_set_test: RuntimeError # is-checks do not implement strong mode type system
 int_parse_radix_test/01: RuntimeError
 int_parse_radix_test/02: RuntimeError

[Leaf, 2017/08/24 17:30:09]

File a bug for these?

+string_split_test: RuntimeError # does not return List<String>
 
 [ $compiler == dart2js && $runtime == drt && $csp && $minified ]
 core_runtime_types_test: Pass, Fail # Issue 27913
 
 [ $compiler != dartdevc ]
 error_stack_trace_test/static: MissingCompileTimeError
 iterable_element_at_test/static: MissingCompileTimeError
 
 [ $compiler == dartdevc && $runtime != none ]
 error_stack_trace_test/nullThrown: RuntimeError # .stackTrace not present for exception caught from 'throw null;'
@@ skipping 260 matching lines @@
 string_from_environment2_test: Skip
 string_from_environment3_test: Skip
 string_from_environment_test: Skip
 
 [ $system == windows && $arch == x64 ]
 stopwatch_test: Skip  # Flaky test due to expected performance behaviour.
 
 [ $runtime == vm ]
 string_case_test/01: RuntimeError
 
+[ $runtime == vm || $runtime == dart_precompiled ]
+string_split_test: RuntimeError # does not return List<String>
+
 [ $compiler == dart2js && $dart2js_with_kernel && $host_checked ]
 apply2_test: Crash
 apply3_test: Crash
 apply4_test: Crash
 apply5_test: Crash
 apply_test: Crash
 big_integer_arith_vm_test/modInv: Crash
 big_integer_arith_vm_test/shift: Crash
 bit_twiddling_bigint_test: Crash
 bool_from_environment2_test/01: MissingCompileTimeError
@@ skipping 482 matching lines @@
 int_parse_radix_bad_handler_test: Pass
 
 [ $compiler == dart2analyzer && $strong && $checked ]
 iterable_fold_test/01: CompileTimeError
 
 [ $compiler == dart2analyzer && $checked && !$strong ]
 iterable_fold_test/01: Pass
 
 [ $compiler == dart2analyzer && $strong  && !$checked ]
 iterable_fold_test/01: CompileTimeError