OP-TEE TA flag changes across version update

An OP-TEE TA has the TA flag which specifies important characteristics like whether it is a single- or multi-instance TA. This flag can change across version update. Thus, we should flush the cached TA flag when the TA gets updated.

#865

No file or test path is named. Trace the OP-TEE TA update path and locate where the TA flag is cached; then verify that an update refreshes the cached flag so its new instance characteristics are used.

Written by the indexing model from the issue text.