[REVIEW-3-6] Java com.sun.star.comp.helper.Bootstrap.cppuhelper_bootstrap fixes

For various reasons, bootstrapping UNO in a Java process (i.e., one 
started by calling the "java" executable) got broken (at least 
bootstrapping native, binary UNO in such a process, by calling 
com.sun.star.comp.helper.Bootstrap.cppuhelper_bootstrap).  This does not 
affect LO itself, but can affect external Java applications that use LO.

So please review the relevant fixes

<http://cgit.freedesktop.org/libreoffice/core/commit/?id=e7a02843e54e1b64e2078549af110beaccf50348> 
"Export JNI functions from juh, juhx libs"

and

<http://cgit.freedesktop.org/libreoffice/core/commit/?id=9fc870fc33c2872aa93477523da4a54c841cf9b5> 
"ServiceManager::createInstanceWithContext needs to honor given Context"

from master for cherry-picking to libreoffice-3-6.  Another useful fix 
would be

<http://cgit.freedesktop.org/libreoffice/core/commit/?id=f98379816411f932ccdafede5f9b25c260c17361> 
"Make ure/source/uretest work again"

to make the relevant (manual) tests work again, but it is not strictly 
necessary.

Thanks,
Stephan