This CL further extends the debug wrapper, migrates around 60 tests, and
removes a few tests that use functionality we will not support anymore.

In more detail:

* Removed tests that use:
  * enable/disable individual breakpoints
  * invocationText()
  * the ScriptCollected event
  * showBreakPoints
  * evalFromScript (and similar)
  * mirror.constructedBy and mirror.referencedBy
  * event_data.promise()
* Some frame.evaluate uses were adapted since due to differences between
  remote objects (inspector) and mirrors. For instance, exceptions are
  currently not recreated exactly, since the inspector protocol does not
  give us the stack and message separately. Other objects (such as
  'this' in debug-evaluate-receiver-before-super) need to be explicitly
  converted to a string before the test works correctly.
* Ensure that inspector stores the script before sending ScriptParsed and
  ScriptFailedToParse events in order to be able to use the script from
  within those events.
* Better remote object reconstruction (e.g. for undefined and arrays).
* New functionality in wrapper:
  * debuggerFlags().breakPointsActive.setValue()
  * scripts()
  * execState.setVariableValue()
  * execState.scopeObject().value()
  * execState.scopeObject().property()
  * execState.frame().allScopes()
  * eventData.exception()
  * eventData.script()
  * setBreakPointsActive()

BUG=v8:5530

Review-Url: https://codereview.chromium.org/2497973002
Cr-Commit-Position: refs/heads/master@{#41019}