[Bug] Fenix UI test reports logging success with failures

[AaronMT]

I believe starting with the changes we added in #10089 I am seeing Matrix Results report as failure but logged as success for the past couple days since this landed.

I think this is happening due to the following

$JAVA_BIN -jar $FLANK_BIN android run \
	--config=$flank_template \
	--max-test-shards=$num_shards \
	--app=$APK_APP --test=$APK_TEST \
	--local-result-dir="${RESULTS_DIR}" \
	--project=$GOOGLE_PROJECT \
	| tee flank.log

exitcode=$?
failure_check

I believe the tee call is overwriting the exit check we want from calling Flank just prior 🙃

┆Issue is synchronized with this Jira Task