Revert "VTS: Test that configs in a group differ only by vsync period"

This reverts commit 6f36dd6e.

Differing only by vsync period was not a requirement on Android R, and
it shouldn't be added after-the-fact to an existing HAL version.

There are devices on the market that switch seamlessly between configs
that differ in resolution/dpi, and therefore have those configs in a
common group.

Bug: 200184776
Change-Id: Id0bfc67e55d5139fddb2b359cabafd9281c33734