Review finding (MAJOR-1): masking the first argument of every new RegExp(...)
also hid `el.innerHTML = new RegExp("<script src=x></script>").source`, a real
injection through .source — desktop_surface_findings returned 0 findings for
that line. The literal is now masked only when the constructor is the argument
of .replace/.replaceAll/.split/.match/.matchAll/.search or the receiver of
.test/.exec; every other use (.source, .toString(), template interpolation) is
a string-builder and keeps firing. The existing test gains the .source line
(must flag) and a .test() line (must not).
5765f8d190