src: move error handling code into node_errors.cc
Move the following code into a new node_errors.cc file and declare them in node_errors.h for clarity and make it possible to include them with node_errors.h.
- AppendExceptionLine()
- DecorateErrorStack()
- FatalError()
- OnFatalError()
- PrintErrorString()
- FatalException()
- ReportException()
- FatalTryCatch
And move the following definitions (declared elsewhere than node_errors.h) to node_errors.cc:
- Abort() (in util.h)
- Assert() (in util.h)