Added use of "mkdir" task to avoid error when output directory does not exist, since "javac" does not create it.
Added use of "mkdir" task to avoid error when output directory does not exist, since "javac" does not create it.

git-svn-id: d596a19132b705a85694e062da4def6039642bfb@1084 4d38ed0c-b8d3-11de-a71d-8f2b2e058ad8

borisbrodski/jmockit,borisbrodski/jmockit