common: OpTracker age histogram calculation is not correct

common: OpTracker age histogram calculation is not correct

While the TrackedOps in each sharded list are ordered, there are no
order among different shared lists. Looping the sharded list one by one
won't be able to get the right histogram. Instead, we can increment the
bin count for each of the TrackedOp. Btw, for those TrackedOp whose age
is >= 2^30 ms, they are now been put in the respective number of bits
bin, instead of been put in a single bin.

Signed-off-by: Zhiqiang Wang <zhiqiang.wang@intel.com>