Revert "dart2js: add support for configuration-specific imports."

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.
 
 [ $compiler == none ]
 built_in_identifier_prefix_test: Fail # Issue 6970
 tearoff_constructor_basic_test: Skip # Crashes in checked mode -- hausner investigating
@@ skipping 13 matching lines @@
 # Non-contractive types are not supported in the vm.
 cyclic_type_test/02: Fail, OK
 cyclic_type_test/04: Fail, OK
 cyclic_type2_test: Fail, OK
 least_upper_bound_expansive_test/*: Fail, OK
 
 async_star_regression_2238_test: CompileTimeError, RuntimeError # drt only runtime-errs.
 async_star_cancel_while_paused_test: RuntimeError
 async_star_await_pauses_test: Skip # Times out. Issue 23996
 
-# Unsupported configuration specific imports.
-config_import_test: RuntimeError
-
 [ $compiler == none && $runtime == vm ]
 class_keyword_test/02: MissingCompileTimeError # Issue 13627
 unicode_bom_test: Fail # Issue 16067
 vm/debug_break_enabled_vm_test/01: Crash, OK # Expected to hit breakpoint.
 try_catch_optimized1_test: Skip # Srdjan investigating
 
 [ $compiler == none && $checked ]
 type_variable_bounds4_test/01: Fail # Issue 14006
 
 [ $compiler == none ]
@@ skipping 86 matching lines @@
 deferred_constraints_constants_test: Skip
 deferred_global_test: Skip
 deferred_inheritance_constraints_test: Skip
 
 deopt_inlined_function_lazy_test: Pass, Crash # Incompatible flag: --deoptimize-alot
 tearoff_basic_test: RuntimeError, Crash # Conflicting flag.
 vm/type_cast_vm_test: RuntimeError # Line number mismatch.
 regress_23408_test: RuntimeError
 
 stack_trace_test: Fail  # Issue 24783 - inlined frames missing