Fix a bug in the client

In very rare cases, at the very end of a deflate block, there will be a distance
which has X bits in Huffman code, an end of block symbol with Y bits in Huffman
code and distances have maximum Z bits in Huffman code. If X + Y < Z, then we
incorrectly cache Z bits which we may not have enough bits to cover. This causes
a crash in the client, but it is catchable in the paygen stage.

This patch adds a new parameter in the Puffer to catch these scenarios and adds
a new function RemoveDeflatesWithBadDistanceCaches() which detects and removes
these problematic deflate instances. This function can be called from the
update_engine to do that.

Bug: crbug.com/915559
Test: unittests
Test: puffin_corpus
Change-Id: I450204dc3c0e3f56d263aff47c420eba65f8453b