Autotest: fixes to compile_gwt_clients.

* Added another directory to check for the gwt installation as that's
where it will be installed in the chroot.

* Fixed the extra java args position so they are passed to the java and
not the gwt application.

* Fixed extra_args piping.

BUG=chromium:345023
Test=ensured I can still run compile_gwt_clients and I can build with it
in an ebuild.

Change-Id: I799ff93669f21b94d4c216cb756898dcb6d779d7
Reviewed-on: https://chromium-review.googlesource.com/187292
Reviewed-by: Simran Basi <sbasi@chromium.org>
Tested-by: Simran Basi <sbasi@chromium.org>
Commit-Queue: Simran Basi <sbasi@chromium.org>
1 file changed