Fix state management issue for tracing - #5062

Improve the performance of taking a heap snapshot - #5134

Retire broken import/export feature - #5135

Debugger updates

Added support for viewing profiler hits in the debugger script viewer - #4831

Added support for inspecting records - #5084

General updates

Fix several issues in syntax highlighting that would color variable names that contain reserved words incorrectly and leave extends/implements clauses uncolored for some classes - #4948

Fix an issue in Safari (browsers that do not support RegExp negative lookbehind) that prevented DevTools from loading - #4938

Fix an issue that would prevent DevTools connecting to the backend server that would disable some functionality - #5016