Generalize the first argument in an assert to be an expression (issue 26865)

tests/corelib/corelib.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.
 
 [ $compiler == none && ($runtime == drt || $runtime == dartium) ]
 bool_from_environment2_test: Skip
 bool_from_environment_test: Skip
 from_environment_const_type_test: Skip
 from_environment_const_type_undefined_test: Skip
 int_from_environment2_test: Skip
@@ skipping 121 matching lines @@
 [ $compiler == dart2analyzer && $checked ]
 from_environment_const_type_undefined_test/09: CompileTimeError
 from_environment_const_type_undefined_test/11: CompileTimeError
 from_environment_const_type_undefined_test/12: CompileTimeError
 from_environment_const_type_undefined_test/13: CompileTimeError
 from_environment_const_type_undefined_test/14: CompileTimeError
 from_environment_const_type_undefined_test/16: CompileTimeError
 
 [ $compiler == dart2analyzer ]
 int_parse_radix_bad_handler_test: fail
-list_insert_test: fail
-list_removeat_test: fail
 hash_set_type_check_test: StaticWarning, OK # Tests failing type tests.
 error_stack_trace_test: StaticWarning, OK # Test generates errors on purpose.
 iterable_element_at_test: StaticWarning, OK # Test generates errors on purpose.
 num_clamp_test: StaticWarning, OK # Test generates errors on purpose.
 string_test: StaticWarning, OK # Test generates error on purpose.
 duration2_test: StaticWarning, OK # Test generates error on purpose.
 
 [ $system == windows && $arch == x64 ]
 stopwatch_test: Skip  # Flaky test due to expected performance behaviour.
 
@@ skipping 45 matching lines @@
 int_parse_radix_test: Pass, Timeout # --no_intrinsify
 
 [ $compiler == precompiler || $runtime == dart_app ]
 data_resource_test: Skip # Resolve URI not supported yet in product mode.
 package_resource_test: Skip # Resolve URI not supported yet in product mode.
 file_resource_test: Skip # Resolve URI not supported yet in product mode.
 http_resource_test: Skip # Resolve URI not supported yet in product mode.
 
 [ $arch == simdbc || $arch == simdbc64 ]
 regexp/stack-overflow_test: RuntimeError, OK # Smaller limit with irregex interpreter