Disable concurrency for chrome on mac

[vweevers]

Chrome @ OSX: it's not possible to launch multiple instances of Chrome at once
https://github.com/httptoolkit/browser-launcher#known-issues

Windows had a similar issue with IE. For that reason I added a mechanism to disable concurrency.

system/index.js

Lines 51 to 53 in 6542833

	// Can't run multiple processes if they're killed by image name
	// (and IE doesn't support it for additional, unknown reasons).
	supports.concurrency = false

Do the same for chrome on mac.