The satellite now returns the last interval_end_time for each
daily storage usage.
We need to store the interval_end_time in the storage usage cache.
Also, renamed interval_start to timestamp to avoid ambiguity since
the interval_start only stores just the date/day returned by the
satellite.
Updates https://github.com/storj/storj/issues/4178
Change-Id: I94138ba8a506eeedd6703787ee03ab3e072efa32
It seems the tests relied on time.Now(), which might cause some
discrepancies in calculations. Use a fixed time.Now() rather than
recalculating.
As a sidefix, remove "Test" prefix from t.Run. These are unnecessary.
Change-Id: I1de903fcf0fcf46fc8e3acf2463e17239b8e3cc6
