Tracking issue for the LLVM 22 upgrade

[alexrp]

• Consider switching *-uefi-* targets to uefi instead of windows for LLVM 21+ #21630
• [PowerPC][AIX] Specify correct ABI alignment for double llvm/llvm-project#144673 (data layout change)
• [ARM] support -mlong-calls -fPIC on arm32 #39970 llvm/llvm-project#147313
• [PowerPC] Change half to use soft promotion rather than PromoteFloat llvm/llvm-project#152632
• [AVR] Change half to use softPromoteHalfType llvm/llvm-project#152783
• [SPARC] Change half to use soft promotion rather than PromoteFloat llvm/llvm-project#152727
• [WebAssembly] Change half to use soft promotion rather than PromoteFloat llvm/llvm-project#152833

• zig/test/llvm_targets.zig

  Lines 355 to 356 in bb79c85

  	// .{ .cpu_arch = .xtensa, .os_tag = .freestanding, .abi = .none },
  	// .{ .cpu_arch = .xtensa, .os_tag = .linux, .abi = .none },

• zig/test/llvm_targets.zig

  Line 242 in bb79c85

  // .{ .cpu_arch = .s390x, .os_tag = .zos, .abi = .none },

Previous upgrade: #23176