Added all test dependencies to libprocess' tests target.

We rely on some additional tools beyond the currently listed being
present. Since they are already listed in `check_PROGRAMS` to make
`make check` work, just reuse that variable here instead of expanding
the full list by hand.

Review: https://reviews.apache.org/r/52677/

3rdparty/libprocess/Makefile.am

@@ -307,7 +307,7 @@ check-local: tests
 	./libprocess-tests
 
 tests: all $(BUNDLED_DEPS)
-	$(MAKE) $(AM_MAKEFLAGS) libprocess-tests benchmarks
+	$(MAKE) $(AM_MAKEFLAGS) $(check_PROGRAMS)
 
 # TODO(benh): Fix shared builds (tests need libglog, libev, etc).