Add fjcvtzs instruction for ARMv8.3 target

[CrazyboyQCD]

Closes #4062.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 53.14%. Comparing base (6ddc2b4) to head (0ad66e7).
Report is 317 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4084      +/-   ##
==========================================
+ Coverage   47.24%   53.14%   +5.90%     
==========================================
  Files         476      484       +8     
  Lines       46892    48223    +1331     
==========================================
+ Hits        22154    25630    +3476     
+ Misses      24738    22593    -2145     

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[jasonwilliams]

This is very cool @CrazyboyQCD!

Do you have a way of testing this as I assume Github Actions don't have any arm runners

[CrazyboyQCD]

Do you have a way of testing this as I assume Github Actions don't have any arm runners

aarch64-apple-darwin is the only one I found that has the jsconv feature, I am not sure if we could use cross to test this.

[hansl]

It does what it says, and I manually tested it on my Mac, checking both the unit tests and the test262 in debug and release, but also verifying that the outputted release ASM contained the instruction at the right place.

LGTM.

[nekevss]

LGTM! Thanks for looking into this @CrazyboyQCD