Move forward installed-files.txt in the dependency graph

Bug: 5265104
- Move installed-files.txt forward to ahead of system.img in the
dependency graph, so that even if the system.img fails to build due to
too large size we can still get the size stats.
- Change the script tools/fileslist.py to sort items in decreasing size.

Change-Id: I5913bc51971e341ffbfcf3fa449c987f126e409b

tools/fileslist.py

@@ -15,7 +15,7 @@
 # limitations under the License.
 #
 
-import os, sys
+import operator, os, sys
 
 def get_file_size(path):
   st = os.lstat(path)
@@ -37,9 +37,9 @@ def main(argv):
           output.append(row)
         except os.error:
           pass
+  output.sort(key=operator.itemgetter(0), reverse=True)
   for row in output:
     print "%12d  %s" % row
 
 if __name__ == '__main__':
   main(sys.argv)
-