Revert "Make Perfetto the default trace engine."

This reverts commit 062e6eb7107d3c868ea3128a74b63d7982b9e07b.

Reason for revert: Perfetto trace post-processing is not quite at parity with atrace yet; reverting until that update is complete.

Change-Id: Id7856cd8860800667e49ca436393af9fa409edb8
3 files changed