... as opposite to a global per-isolate one.
Also streamlined multiple checks into a single acceptsPause() method.
BUG=chromium:590878
Review-Url: https://codereview.chromium.org/2925903002
Cr-Commit-Position: refs/heads/master@{#45749}
Found multiple issues (added TODOs for them):
- isPaused() check is global, so one can resume from another session/context group
without receiving 'paused' notification;
- setBreakpointsActive flag is global affecting all sessions and context groups;
- max async call stack depth is global, and should be per context group.
BUG=chromium:590878
Review-Url: https://codereview.chromium.org/2921373002
Cr-Commit-Position: refs/heads/master@{#45742}
