[INTERNAL] support/trace/E2ETraceLib.js: browser compatibility

- browser compatible utilization of high resolution timestamps
- minor reformatting
- ESLint space-unary-ops error fixed
- removed IIFE in onTransactionStepTimeout
- fixed typo

Change-Id: Ic1128b30f57c287b32459799e13af0c4ef1a90ba

Author: drascs