The patch introduces a dedicated dispatching class for JIT code events. It is
set as a helper on the isolate.
This allows classes across v8 to break their dependency on Logger and CpuProfiler.
These two became just regular clients of the dispatcher.

BUG=v8:4789

Review-Url: https://codereview.chromium.org/2061623002
Cr-Commit-Position: refs/heads/master@{#37005}

Jaideep has been regularly contributing PPC and S390 changes recently.
Adding him as owner/reviewer to PPC / S390 specific directories.

R=joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com, mbrandy@us.ibm.com
BUG=

Review-Url: https://codereview.chromium.org/2024533003
Cr-Commit-Position: refs/heads/master@{#36589}

R=danno@chromium.org,jkummerow@chromium.org,jochen@chromium.org,joransiu@ca.ibm.com,michael_dawson@ca.ibm.com,mbrandy@us.ibm.com
BUG=

Review URL: https://codereview.chromium.org/1802343002

Cr-Commit-Position: refs/heads/master@{#34789}

R=danno@chromium.org,jkummerow@chromium.org,jochen@chromium.org,joransiu@ca.ibm.com,michael_dawson@ca.ibm.com,mbrandy@us.ibm.com
BUG=

Review URL: https://codereview.chromium.org/1768383002

Cr-Commit-Position: refs/heads/master@{#34592}