Update android toolchain variable to point to root dir and not the bin

platform_tools/android/bin/android_gdb_native

 #!/bin/bash
 #
 # android_gdb_native: Pushes gdbserver, connects to specified Skia app,
 #                     and enters command line debugging environment.
 
 SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 source $SCRIPT_DIR/android_setup.sh
 
 # setup the gdbserver
 export BUILDTYPE  # from android_setup.sh
@@ skipping 27 matching lines @@
     echo "continue"
     echo "sharedLibrary ${APP_NAME}"
 
     # Load libskia_android.so here.
     echo "sharedLibrary skia_android"
 } > $GDBSETUP
 
 
 # Launch gdb client
 echo "Entering gdb client shell"
-$ANDROID_TOOLCHAIN/../host_prebuilt/bin/gdb -x $GDBSETUP
+$ANDROID_TOOLCHAIN/host_prebuilt/bin/gdb -x $GDBSETUP
 
 # Clean up:
 # We could 'rm -rf $GDB_TMP_DIR', but doing so would cause subsequent debugging
 # sessions to take longer than necessary. The tradeoff is to now force the user
 # to remove the directory when they are done debugging.
 rm $GDBSETUP