* Improve string parsing and JSON parsing
- fix JSON parsing of non ASCII string contents
- more precise string parsing errors
- more precise JSON parsing errors
- add `JS_ParseState::buf_start` to compute line/column
- fix HTML comment detection at start of source code
- improve v8 Failure messages (pulled and modified `formatFailureText` from **mjsunit.js**)
- ignore more v8 tests
The shell script runs the tests and diffs stdout against v8.txt.
Lines added/removed means tests were broken/fixed.
Future work is to a) fix failing tests, and b) enable more tests.
A number are disabled for various reasons and mjsunit subdirectories are
currently skipped. Need to decide on a case-by-case basis what is and
isn't relevant to us.
At the moment about 430 tests are run of which approx. 80% pass.
