Fix some assertion failures on Fuchsia

runtime/BUILD.gn

 # Copyright (c) 2014, 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.
 
 import("runtime_args.gni")
 
 declare_args() {
   # Instead of using is_debug, we introduce a different flag for specifying a
   # Debug build of Dart so that clients can still use a Release build of Dart
   # while themselves doing a Debug build.
-  dart_debug = false
+  dart_debug = is_debug
 
   # Set the runtime mode. This affects how the runtime is built and what
   # features it has. Valid values are:
   # 'develop' (the default) - VM is built to run as a JIT with all development
   # features enabled.
   # 'profile' - The VM is built to run with AOT compiled code with only the
   # CPU profiling features enabled.
   # 'release' - The VM is built to run with AOT compiled code with no developer
   # features enabled.
   #
@@ skipping 268 matching lines @@
     "third_party/double-conversion/src:libdouble_conversion",
     "vm:libdart_lib_jit",
     "vm:libdart_lib_nosnapshot_with_precompiler",
     "vm:libdart_vm_jit",
     "vm:libdart_vm_nosnapshot_with_precompiler",
   ]
   sources = [
     "vm/libdart_dependency_helper.cc",
   ]
 }