Error parsing params values with =

[Serginho]

= simbol is allowed as a url param value.

Example:
new UrlSearchParams('?param1=valuewith=&param2=bar');

This example breaks un the unexpected value: {param1: valuewith , param2: bar}

expected: {param1: valuewith= , param2: bar}

[alexturpin]

I've run into this issue with base64 encoded values as well. Results for new URLSearchParams('q=GVzdA==').get('q') is GVzdA with the polyfill but in Chrome, Firefox and Edge it's GVzdA==.