[DrJava] another update to build-common.xml

[Eric E. A. <ea...@cs...>]

I had to make another update to the build-common script in order to
prevent a race condition when committing new code. The race condition
involves the spawning of new interactions JVMs, and, at least on Windows
XP, it tends to lock up the commit process (despite the fact that all
tests pass!).  The race condition _may_ be the cause of bug 524123 as
well; I'm still investigating. If so, the new build-common script fixes
that bug.

Anyway, be sure to do a cvs update on build-common again before committing
new code.

Thanks,

-- Eric