Extend CPU profiler with mapping ticks to source lines

This patch applies changes from https://codereview.chromium.org/682143003/ review.

The code introduces instruction_start attribute to CodeEntry class.
Therefore each code entry has at least one instruction mapped to a source location.
This patch also fixes fast/events/window-onerror-02.html chromium test as well as
following v8-crosswalk debug tests:

cctest/test-api/CallICFastApi_SimpleSignature_Miss2WithProfiler
cctest/test-api/CallICFastApi_SimpleSignature_TypeErrorWithProfiler
cctest/test-api/InterceptorCallICFastApi_SimpleSignature_Miss3WithProfiler
cctest/test-api/InterceptorCallICFastApi_SimpleSignature_TypeErrorWithProfiler
cctest/test-profile-generator/NoSamples
cctest/test-profile-generator/RecordTickSample
cctest/test-profile-generator/SampleIds
Merge pull request #59 from eleskine/master

Extend CPU profiler with mapping ticks to source lines