This reverts commit dd6c4f4d "fdo#46102: Load
Java scripts with class loaders that actually find them."  That commit broke
support for macros embedded in documents (as
new java.net.URL("vnd.sun.star.tdoc:...") throws a MalformedURLExcetpion), and
it looks like that commit was not necessary after all -- or rather that what it
tried to work around must have been some other problem that has been fixed
meanwhile.  "It is unclear to me how the Java script provider shall ever have
found the script jars in the past" indicates that something must have been
fishy, and what I failed to notice back then is that createURL creates
java.net.URL instances with a UCBStreamHandler that does allow to obtain content
from weird-looking URLs.

Anyway, with that reverted, all three following scenarios work on both current
master (towards LO 3.7) and libreoffice-3-6 (towards LO 3.6.4); I haven't yet
come around to test on libreoffice-3-5:

1  Stock macros, "Tools - Macros - Run Macro... - LibreOffice Macros -
HelloWorld", running all of the four "helloworld.bsh", "helloworld.js",
"HelloWorldPyhton", and
"org.libreoffice.example.java_scripts.HelloWorld.printHW".

2  Per-document macros, loading test.odt attached to fdo#49517, then "Tools -
Macros - Run Macro... - test.odt - HelloWorld", running
"org.libreoffice.example.java_scripts.HelloWorld.printHW".

3  Extension macros, installing ScriptDispatch.oxt attached to fdo#46012 as
shared extension, then loading StartScriptDispatch.odt attached to fdo#46012 and
pressing the "Start Java via ScriptProvider" button.

Change-Id: I31cd16b3720ffeb1058722d4d1fdffb773f8a067