eatt/unit_test: Extend unit test to verify eatt counter am: 497c7013 am:...

eatt/unit_test: Extend unit test to verify eatt counter am: 497c7013 am: d307144e am: 0747cc2a

Original change: https://android-review.googlesource.com/c/platform/system/bt/+/1477784

Change-Id: Ia6220387e9c3d2a49c282fc0d141d1c823470e75