Simplify rwc runner to use the common functionality to get errors, js files etc as part of harness compilation
Emit the error file contents and highlight it to show errors for rwc errors
Baseline sourcemap record from rwc runner
Fixed the file map lookup to use hasOwnProperty
Merge pull request #495 from Microsoft/rwcRunner

Simplifies RWC Runner to use HarnessCompiler.compileFiles so it can be used to baseline errors and sourcemaps more like compiler runner