By using the bucketForHash function we can loop through and find
some appropriate keys to test the edge-case. This will then
automatically keep the test working even if some internals
of QHash changes.
We do this because certain changes which change the bucket the
pre-selected keys would end up in could make the test a no-op,
without warning. And recent and upcoming changes have changed
both this and erase(). We limit the search-space to
the minimum numBuckets * 4, where minimum numBuckets is current
128.
Change-Id: I13b0bce15ee884144e3248846be34667fb5d35cc
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
26267ef57e