If we're in an Android build tree, we should use core.jar as our "SDK".

This fixes running junit tests for non-public classes, since bdc's --sdk
change went in. While --sdk is perfect for real people, it's probably not
what we want to use ourselves. Since this script is already hard-coded
for use in an Android build tree, this seems like a reasonable place to
apply the fix.
diff --git a/libcore/tools/runner/vogar b/libcore/tools/runner/vogar
index e5a6ad0..cdd800a 100755
--- a/libcore/tools/runner/vogar
+++ b/libcore/tools/runner/vogar
@@ -17,5 +17,8 @@
 # m core-tests junit caliper snod && adb reboot bootloader && fastboot flashall && adb wait-for-device
 # mmm dalvik/libcore/tools/runner
 
-classpath=`dirname $0`/../../../../out/host/linux-x86/framework/dalvik_runner.jar
-exec java -cp $classpath dalvik.runner.DalvikRunner "$@"
+android_root=`dirname $0`/../../../..
+
+classpath=${android_root}/out/host/linux-x86/framework/dalvik_runner.jar
+core_jar=${android_root}/out/target/common/obj/JAVA_LIBRARIES/core_intermediates/classes.jar
+exec java -cp $classpath dalvik.runner.DalvikRunner --sdk ${core_jar} "$@"