MediaMetrics: Change dumpsys format

As the dumpsys no longer needs to be parseable by a program
convert to a more human readable form.

1) Make default time REALTIME consistently.
2) Dump time as a human readable string.
3) Remove dumpsys versioning code.
4) Delimiter changes.

Test: atest mediametrics_tests
Test: adb shell dumpsys media.metrics
Bug: 138583596
Change-Id: I6ee7d81a18e0e220b258c722d232c05805118abb
diff --git a/services/mediametrics/TransactionLog.h b/services/mediametrics/TransactionLog.h
index 0c5d12b..27e2c14 100644
--- a/services/mediametrics/TransactionLog.h
+++ b/services/mediametrics/TransactionLog.h
@@ -155,7 +155,7 @@
             --ll;
             for (const auto &item : itemMap.second) {
                 if (ll <= 0) break;
-                ss << "  { " << item.first << ", " << item.second->toString() << " }\n";
+                ss << "  " << item.second->toString() << "\n";
                 --ll;
             }
         }