Apply the optimization if the individual segment is match all query even though the whole shard is not

[bowenlan-amzn]

Coming from #11083 (comment)

When starting to process each segment, we get the LeafReaderContext which can provide the numDocs of this segment. On the other hand, the weight taking in LeafReaderContext can produce the estimate count of this segment. If these 2 are same, we can treat the weight equivelant as a match-all and it may satisfy the pre-conditions of the fast filters optimization.

[kiranprakash154]

Hi, are we on track for this to be released in 2.12 ?