Shrink JsStr from 24 to 16 bytes

[HalidOdat]

This PR makes the JsStr's len be encoded with TaggedLen reducing the size from 24 to 16 bytes, shaves 5464 bytes from the const RAW_STRINGS array.

The tests have been run under miri and it's happy with the change 🥳

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main

PROGRESS Richards
RESULT Richards 144
PROGRESS DeltaBlue
RESULT DeltaBlue 151
PROGRESS Encrypt
PROGRESS Decrypt
RESULT Crypto 144
PROGRESS RayTrace
RESULT RayTrace 333
PROGRESS Earley
PROGRESS Boyer
RESULT EarleyBoyer 385
PROGRESS RegExp
RESULT RegExp 72.1
PROGRESS Splay
RESULT Splay 527
PROGRESS NavierStokes
RESULT NavierStokes 334
SCORE 218

PR

PROGRESS Richards
RESULT Richards 146
PROGRESS DeltaBlue
RESULT DeltaBlue 152
PROGRESS Encrypt
PROGRESS Decrypt
RESULT Crypto 146
PROGRESS RayTrace
RESULT RayTrace 344
PROGRESS Earley
PROGRESS Boyer
RESULT EarleyBoyer 403
PROGRESS RegExp
RESULT RegExp 74.5
PROGRESS Splay
RESULT Splay 534
PROGRESS NavierStokes
RESULT NavierStokes 348
SCORE 224
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[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	50,595	50,595	0
Passed	47,238	47,238	0
Ignored	1,964	1,964	0
Failed	1,393	1,393	0
Panics	0	0	0
Conformance	93.36%	93.36%	0.00%