As part of the efforts in tdf#146266 to move parts of the codebase from
the older makefile.mk build system to the newer gbuild system, this
commit migrates the WeakBag test, and cleans it up a little.
The test can now be invoked using this command:
$ make CppunitTest_comphelper_weakbag
Change-Id: I4ac3771fa23e28abd38a2dab84cacd1ae57fb70f
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/165591
Tested-by: Hossein <hossein@libreoffice.org>
Reviewed-by: Hossein <hossein@libreoffice.org>
804caab067