This adds a wrapper class around the inspector protocol for use in
debugger tests. The interface is intended to stay similar to the
currently exposed DebuggerContext.
Right now, we support adding a listener, (partial) handling of the
AfterCompile event, and enabling/disabling the debugger.
BUG=v8:5530
Review-Url: https://codereview.chromium.org/2451153003
Cr-Commit-Position: refs/heads/master@{#40635}
