JS backend: added jsCode test cases
JS backend: added jsCode definition
JS backend: expand jsCode at translator
JS backend minor: formatting
JS parser: removed @ from @author tag because of JetCodeConformanceTest
JS parser: fixed labelled break/continue
JS parser: fixed messages loading
JS parser: save token positions
JS backend: pass diagnostics to TranslationContext using config
JS parser: pass ErrorReporter to JsParser
JS parser: report diagnostic when parser encounters errors
JS parser: fixed JsInvocation mapping
JS parser: removed unused decompilation info
JS parser: removed unused classes and methods