Remove obsolete uses of LOCAL_MODULE_TAGS

Only LOCAL_MODULE_TAGS := tests is used is meaningful in the current
implementation.  "optional" and "samples" both exist in the tree, but
are meaningless.  "gnu", "user", "eng" and "debug" are  no longer used,
and are already forbidden by the unusual tags check.  The info from the
"module" target is now available in module-info.json.  Delete all the
irrelevant code.

Test: no change to out/build-aosp_cf_x86_64_phone.ninja
Change-Id: I04e8178a362e382a1a4bd997c1b4c3a480db7714