[jsinterp] Fix division

[bashonly]

Fixes failing nsig decryption for new YT JS player 8c7583ff

See ytdl-org/youtube-dl#32292

Zero divided by any non-zero number was returning NaN

[debug] JS:                     c[new Date("1970-01-01T09:15:00.000+09:15")/1E3]
[debug] JS:                       new Date("1970-01-01T09:15:00.000+09:15")/1E3
[debug] JS:                         "1970-01-01T09:15:00.000+09:15"
[debug] JS:                         -> '1970-01-01T09:15:00.000+09:15' <-| "1970-01-01T09:15:00.000+09:15"
[debug] JS:                         0
[debug] JS:                         1E3
[debug] JS:                         -> 1000.0 <-| 1E3
[debug] JS:                       -> nan <-| new Date("1970-01-01T09:15:00.000+09:15")/1E3
[debug] JS:                     => Raises: Cannot get index nan in: [F<247>, -1658198590, ..., -1183556064, -705166834, -1680476002, 208789974] <-| c[new Date("1970-01-01T09:15:00.000+09:15")/1E3]

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Copilot Summary

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Summary

🧪🐛➗

Fix JavaScript division operator in yt_dlp/jsinterp.py and add a test case in test/test_jsinterp.py to verify its behavior.

_js_div fixed
Zero division bug no more
Autumn tests pass now

Walkthrough

• Fix JavaScript division operator / to return inf or -inf when dividing by zero, instead of nan (link)
• Add test case for JavaScript division operator / with different values, such as zero, undefined, and infinity (link)
• Use JSInterpreter class from yt_dlp/jsinterp.py to evaluate and call a simple JavaScript function that performs division in the test case (link)
• Assert that the results match the expected values according to the JavaScript specification in the test case (link)

[coletdjnz]

Add a nsig test for player 8c7583ff too (in test_YouTube_signature)