The child (==lower level) cache stats in drcachesim today are only for the immediately lower level. This is a holdover from the original implementation which didn't support other than 2 levels. For multiple levels, one would expect the child stats to include the sum of all the lower levels. We fix that here and add a unit test.
The difference is clear in the config file test: LLC stats: Child hits: 147 => LLC stats: Child hits: 174,695
But to avoid flakiness we do not update its regex and rely on the unit test.
Fixes #5190 (closed)