Fixing Readback Test failures related to auto-succeed

Prior implementation failed to clear command reader, causing test to
fail in TearDown.  Transform Readback Tests failed to return if readback
was not supported, moved GTEST_SUCCEED into test body from SetUp

Bug: 111563608
Test: ./VtsHalGraphicsComposerV2_2TargetTest
Change-Id: I4647f94efa216b219d0ef345df1ec3aa81dab4c0