Fix dart_analyzer finding SDK after core_runtime.dart rename

compiler/scripts/dart_analyzer.sh

 #!/bin/bash --posix
 # 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.
 
 set -e
 
-SCRIPT_DIR=$(dirname $0)
-DART_ANALYZER_HOME=$(dirname $SCRIPT_DIR)
+# Setting SCRIPT_DIR this way is ugly, but is needed to handle the case where
+# dart-sdk/bin has been symlinked to. On MacOS, readlink doesn't work
+# with this case.
+SCRIPT_DIR="$(cd "${0%/*}" ; pwd -P)"
+DART_ANALYZER_HOME="$(cd "${SCRIPT_DIR%/*}" ; pwd -P)"
 
 FOUND_BATCH=0
 FOUND_SDK=0
 for ARG in "$@"
 do
   case $ARG in
     -batch|--batch)
       FOUND_BATCH=1
       ;;
     --dart-sdk)
       FOUND_SDK=1
       ;;
     *)
       ;;
   esac
 done
 
 DART_SDK=""
 if [ $FOUND_SDK = 0 ] ; then
-  if [ -f $DART_ANALYZER_HOME/lib/core/core_runtime.dart ] ; then
+  if [ -f $DART_ANALYZER_HOME/lib/core/core.dart ] ; then
     DART_SDK="--dart-sdk $DART_ANALYZER_HOME"
   else
     DART_SDK_HOME=$(dirname $DART_ANALYZER_HOME)/dart-sdk
     if [ -d $DART_SDK_HOME ] ; then
       DART_SDK="--dart-sdk $DART_SDK_HOME"
     else
       DART_SDK_HOME=$(dirname $DART_SDK_HOME)/dart-sdk
       if [ -d $DART_SDK_HOME ] ; then
         DART_SDK="--dart-sdk $DART_SDK_HOME"
       else
@@ skipping 27 matching lines @@
   # On other architectures
   # -batch invocations will do better with a server vm
   # invocations for analyzing a single file do better with a client vm
   if [ $FOUND_BATCH = 0 ] ; then
     EXTRA_JVMARGS+=" -client "
   fi
 fi
 
 exec java $EXTRA_JVMARGS $DART_JVMARGS -ea -classpath "@CLASSPATH@" \
   com.google.dart.compiler.DartCompiler ${DART_SDK} $@