test: fix x86_64-macos failures

This is just a temporary fix - I would like to unify all of x86_64
tests across linux and macos OSes.

test/incremental/x86_64-linux/assert_function.3.zig

@@ -0,0 +1,22 @@
+pub fn main() void {
+    add(3, 4);
+}
+
+fn add(a: u32, b: u32) void {
+    const c = a + b; // 7
+    const d = a + c; // 10
+    const e = d + b; // 14
+    const f = d + e; // 24
+    const g = e + f; // 38
+    const h = f + g; // 62
+    const i = g + h; // 100
+    const j = i + d; // 110
+    assert(j == 110);
+}
+
+pub fn assert(ok: bool) void {
+    if (!ok) unreachable; // assertion failure
+}
+
+// run
+//