Fix a spaces-in-path problem with the dart_analyzer.bat script.

compiler/scripts/dart_analyzer.bat

 @echo off
 rem #!/bin/bash --posix
 rem Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 rem for details. All rights reserved. Use of this source code is governed by a
 rem BSD-style license that can be found in the LICENSE file.
 rem 
 rem stop if any of the steps fails
 rem set -e
 rem 
 
 rem SCRIPT_DIR=$(dirname $0)
 set SCRIPT_DIR=%~dp0
 if %SCRIPT_DIR:~-1%==\ set SCRIPT_DIR=%SCRIPT_DIR:~0,-1%
 
 rem DART_ANALYZER_HOME=$(dirname $SCRIPT_DIR)
-for /f %%i in ('echo %SCRIPT_DIR%') do set DART_ANALYZER_HOME=%%~dpi
+for %%A in ("%SCRIPT_DIR\..") do set "DART_ANALYZER_HOME=%%~fA"
 if %DART_ANALYZER_HOME:~-1%==\ set DART_ANALYZER_HOME=%DART_ANALYZER_HOME:~0,-1%
 
 set FOUND_BATCH=0
 set FOUND_SDK=0
 for %%a in (%*) do (
   if [%%a] == [--batch] set FOUND_BATCH=1
   if [%%a] == [-b] set FOUND_BATCH=1
   if [%%a] == [--dart-sdk]  set FOUND_SDK=1
 )
 
@@ skipping 103 matching lines @@
 rem   fi
 rem fi
 rem 
 
 java %EXTRA_JVMARGS% %DART_JVMARGS% -ea -classpath "@CLASSPATH@" ^
   com.google.dart.compiler.DartCompiler %DART_SDK% %*
 
 rem exec java $EXTRA_JVMARGS $DART_JVMARGS -ea -classpath "@CLASSPATH@" \
 rem   com.google.dart.compiler.DartCompiler ${DART_SDK} $@
 rem