Add a VTS test for DISPLAY_DECORATION

Check for support via getDisplayDecorationSupport. If it is supported,
verify that we can allocate a buffer of the correct format and that
Composition.DISPLAY_DECORATION can be used without error. If it's not
supported, expect an error of EX_UNSUPPORTED_OPERATION.

Bug: 209458568
Fixes: 209458568
Test: atest VtsHalGraphicsComposer3_TargetTest (this)
Change-Id: I0a62a0ce3f8fd3a2d6088f94ce1ad0840d9c6faa