As we add tracing to more types of runtime activity, `--trace-ops` is
less useful of a name. `--trace-leaks` better reflects that this feature
traces both ops and timers, and will eventually trace resource opening
as well.
This keeps `--trace-ops` as an alias for `--trace-leaks`, but prints a
warning to the console suggesting migration to `--trace-leaks`.
One test continues to use `--trace-ops` to test the deprecation warning.
---------
Signed-off-by: Matt Mastracci <matthew@mastracci.com>