Let make-mozilla-sdk.sh copy the python build scripts needed for
JarMaker.py and Preprocessor.py

This shouldn't break anything (hopefully) since the newer scripts are just being
added in addition. New dep versions will be needed before making the
switch in nightingale-hacking.
fix a build error

Amended:
D'oh. Now actually fix the nanojit build error.
for whatever reason, symbolstore.py is needed before xulrunner is built