internal: remove obsolete `rsemWarnUnsafeCode` #4106

Job	Run time
Provide additional context for the workflow	5s
Build release binaries (Linux)	11m 17s
Build release binaries (macOS)	10m 9s
Build docs and release artifacts (Linux)	15m 31s
Build source archive	4m 20s
Build docs and release artifacts (macOS)	10m 54s
Build and test tooling (Linux)	4m 43s
Test the compiler and stdlib (Linux, batch #0)	8m 48s
Build and test tooling (macOS)	4m 46s
Test the compiler and stdlib (Linux, batch #1)	10m 54s
Test the compiler and stdlib (macOS, batch #0)	10m 7s
Test the compiler and stdlib (macOS, batch #1)	8m 57s
Build release artifacts from source archive (Linux)	18m 29s
Build release artifacts from source archive (macOS)	13m 12s
Test release artifacts	1m 50s
All check passed	1s
	2h 14m 3s

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