Use 'globalThis' instead of 'this' when trying to attach a debugger to the
current global to avoid subtle footguns with the varied definitions of 'this'.
The debugger interface needs a true GlobalObject so this is much clearer. In
particular, this is a problem in test_nativewrappers.js when the test runs in
strict mode since the 'this' in the test function is no long implicitly the
global.
Differential Revision: https://phabricator.services.mozilla.com/D157544
Alexandre Poirot