Fix for function type assignable check.

tests/language/language_analyzer.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 == dartanalyzer ]
 
 # Runtime negative test. No static errors or warnings.
 closure_call_wrong_argument_count_negative_test: skip
 
 # TBD: using built-in identifers
@@ skipping 24 matching lines @@
 f_bounded_quantification_test/01: fail
 f_bounded_quantification_test/02: fail
 
 function_type_alias9_test/00: crash # Issue 11987
 
 list_literal_syntax_test/01: fail # Issue 12103
 list_literal_syntax_test/02: fail # Issue 12103
 list_literal_syntax_test/03: fail # Issue 12103
 malformed_test/none: fail
 
-# TBF: '(bool) -> void' is not a subtype of type '([bool]) ->', and rule for assigning function types is not the same as for interface types
-positional_parameters_type_test: fail
-
 # TBF: non-const superinitializer; 7.6.3 Constant Constructors: The superinitializer that appears, explicitly or implicitly, in the initializer list of a constant constructor must specify a constant constructor of the superclass of the immediately enclosing class.
 non_const_super_negative_test: fail
 
 # TBF: 1is int; invalid character in number
 number_identifier_negative_test: fail
 
 # TBF: we should check conflicts not only for methods, but for accessors too
 override_field_test/01: fail
 override_field_test/02: fail
 override_field_test/03: fail
@@ skipping 233 matching lines @@
 factory_redirection_test/09: fail
 factory_redirection_test/10: fail
 factory_redirection_test/11: fail
 factory_redirection_test/12: fail
 factory_redirection_test/13: fail
 factory_redirection_test/14: fail
 getters_setters2_test/03: fail
 type_variable_bounds3_test/00: fail
 type_variable_bounds2_test/05: fail