git: 4fdf604ba667..e15a4f0a320e - vendor/llvm-project/release-18.x - vendor branch updated

[Dimitry Andric]

The branch vendor/llvm-project/release-18.x has been updated by dim:

URL: https://cgit.FreeBSD.org/src/log/?id=4fdf604ba667..e15a4f0a320e

e15a4f0a320e Vendor import of llvm-project branch release/18.x 
llvmorg-18.1.0-rc2-53-gc7b0a6ecd442.