Turn on mbranch-protection=pac-ret only, JIT is broken with BTI enabled
    
    WebKitGTK JIT crashes on aarch64 hardware with new ARMv8.5 BTI
    extension, most commonly seen on M2 Macs running Fedora Asahi. This
    breaks large parts of GNOME using WebKitGTK, notably GNOME Online
    Accounts; GNOME Help; and other similar things.
    
    This removes Asahi specific changes as this could occur on any aarch64
    hardware with this feature and makes WebKitGTK pretty much unuseable
    without this change.
    
    We also reduced generated debuginfo for aarch64 here as the memory
    requirements are pretty huge for -g, making aarch64 rpms unbuildable in
    copr without this change.
    
    Reference: https://bugs.webkit.org/show_bug.cgi?id=245697
    Related: rhbz#213000