JS_DetectModule gives false positive on dynamic imports

[andrieshiemstra]

.e.g a script like import('foo.js').then((a) = {}); now gives true in JS_DetectModule.

In 0.6.1 it was (correctly) false

[andrieshiemstra]

hmm, actually it's worse.. pretty much every string I throw at it returns true?

[bnoordhuis]

See #610 (comment) but basically: working as expected, just differently than before.

[andrieshiemstra]

Thanks.