Remove CFI workarounds after bumping mimimum Xcode version to 26

[filipnavara]

Just posting this for tracking. In #114982 (comment) we discussed an issue with Apple linker that needed a workaround by placing .cfi_startproc/.cfi_endproc around .alt_entry labels. The bug has been fixed in Xcode 26 (as of Beta 6, but possibly earlier) and I verified that it's now working as expected.

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