Attempt to fix test

Author: Danielkonge

test/behavior/abs.zig

@@ -343,11 +343,6 @@ test "@abs float vectors" {
     if (builtin.zig_backend == .stage2_riscv64) return error.SkipZigTest;
     if (builtin.zig_backend == .stage2_x86_64 and builtin.target.ofmt != .elf and builtin.target.ofmt != .macho) return error.SkipZigTest;
 
-    // https://github.com/ziglang/zig/issues/12827
-    if (builtin.zig_backend == .stage2_llvm and
-        builtin.os.tag == .macos and
-        builtin.target.cpu.arch == .x86_64) return error.SkipZigTest;
-
     @setEvalBranchQuota(2000);
     try comptime testAbsFloatVectors(f16, 1);
     try testAbsFloatVectors(f16, 1);

test/behavior/vector.zig

@@ -106,6 +106,12 @@ test "vector float operators" {
     if (builtin.zig_backend == .stage2_c and builtin.cpu.arch.isArm()) return error.SkipZigTest;
     if (builtin.zig_backend == .stage2_x86_64 and builtin.target.ofmt != .elf and builtin.target.ofmt != .macho) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_llvm and builtin.cpu.arch == .aarch64) {
+        // Triggers an assertion with LLVM 18:
+        // https://github.com/ziglang/zig/issues/20680
+        return error.SkipZigTest;
+    }
+
     const S = struct {
         fn doTheTest(T: type) !void {
             var v: @Vector(4, T) = .{ 10, 20, 30, 40 };