CacheStorage: Update PeakParallelSharedOps histogram to use smaller buckets.

Previously this histogram used a max range of 1000 which resulted in rather
course grained buckets.  This CL reduces the histogram max range to 100
while keeping the same number of buckets in order to make the buckets more
granular.  The name is also updated to PeakParallelSharedOps2.

Bug: 985379
Change-Id: Id6f703daeb4851db362142edbe80be05d26fcbb6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1742047
Reviewed-by: Brian White <bcwhite@chromium.org>
Commit-Queue: Ben Kelly <wanderview@chromium.org>
Cr-Commit-Position: refs/heads/master@{#685782}