In addition to top source-destination pairs,
bytecode_dispatches_report.py now prints the hottest bytecode handlers
by the number of times they are executed and dispatch to another one,
regardless of the dispatch target.

Be aware that this figure does not match the number of times a handler
is executed for those which may not or will never dispatch, e.g.
Return or Throw.

BUG=v8:4899
LOG=N

Review URL: https://codereview.chromium.org/1875263004

Cr-Commit-Position: refs/heads/master@{#35629}