Once  a range is found to have a conflict, split around all the calls it
crosses over, since it will anyway have conflicts there, too.

Incrementally, from the last change to greedy, this change brings
overall improvement in benchmarks. In fact, except for 2 regressions
in Jetstream (splay-latency and date-format-xparb, at 6 and 7%
respectivelly), everything else is in the green or noise. Quite a few
benchmarks are over 3%, with a few (zlib, for example) in the double
digits.

Review URL: https://codereview.chromium.org/1328783002

Cr-Commit-Position: refs/heads/master@{#30579}