Removes dependency on v8 from dartc testing

compiler/scripts/dartc_test.sh

-#!/bin/bash
-# Copyright (c) 2011, 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.
-
-set -e
-
-case $(uname -s) in
-    *Linux*|*linux*)
-        OS="linux"
-        ;;
-    Darwin)
-        OS="mac"
-        ;;
-    *)
-        OS="generic"
-        ;;
-esac
-
-SCRIPT_DIR=$(dirname $0)
-DARTC_HOME=$(dirname $SCRIPT_DIR)
-DARTC_LIBS=$DARTC_HOME/lib
-D8_EXEC=${D8_EXEC:-@D8_EXEC@}
-DART_SCRIPT_NAME=${DART_SCRIPT_NAME:-$(basename $0)}
-
-if [ -x /usr/libexec/java_home ]; then
-  export JAVA_HOME=$(/usr/libexec/java_home -v '1.6+')
-fi
-
-# Limit heap in order to detect any memory issues.  
-# On some system, the heap dynamically sizes to > 1GB.
-# Users can specify DART_JVMARGS in the environment to override
-# these settings.
-EXTRA_JVMARGS="-Xmx256M -Xss2M"
-
-exec java $EXTRA_JVMARGS $DART_JVMARGS -ea -Dcom.google.dart.runner.d8="$D8_EXEC" \
-  -Dcom.google.dart.runner.progname="$DART_SCRIPT_NAME" \
-  -classpath "@CLASSPATH@" \
-  com.google.dart.runner.DartRunner $@