make context darwin arm64: removes workaround and uses the label

[devnexen]

directly. LLVM support those since quite some years now.

[codecov]

Codecov Report

Merging #4127 (a8c69d6) into master (ab994a0) will decrease coverage by 0.04%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4127      +/-   ##
==========================================
- Coverage   48.81%   48.77%   -0.05%     
==========================================
  Files          71       71              
  Lines       14280    14280              
==========================================
- Hits         6971     6965       -6     
- Misses       7309     7315       +6     

Impacted Files	Coverage Δ
src/protocol/base.cc	63.15% <0.00%> (-1.98%)	⬇️
src/network/client.cc	46.56% <0.00%> (-0.45%)	⬇️
src/os/async_thread.cc	69.29% <0.00%> (-0.44%)	⬇️
src/server/port.cc	50.27% <0.00%> (+0.27%)	⬆️

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[devnexen]

note I upstreamed this change just today.