chore: import upstream snapshot with attribution

benchmarks/rosetta/gray-code.0

@@ -0,0 +1,34 @@
+fn xorSmall(left: u32, right: u32) -> u32 {
+    var a: u32 = left
+    var b: u32 = right
+    var bit: u32 = 1
+    var out: u32 = 0
+    while a > 0 || b > 0 {
+        if a % 2 != b % 2 {
+            out = out + bit
+        }
+        a = a / 2
+        b = b / 2
+        bit = bit * 2
+    }
+    return out
+}
+
+fn gray(n: u32) -> u32 {
+    return xorSmall(n, n / 2)
+}
+
+pub fn main(world: World) -> Void raises {
+    var ok: Bool = true
+    let expected: [8]u32 = [0, 1, 3, 2, 6, 7, 5, 4]
+    var i: usize = 0
+    while i < 8 {
+        if gray(i as u32) != expected[i] {
+            ok = false
+        }
+        i = i + 1
+    }
+    if ok {
+        check world.out.write("gray code ok\n")
+    }
+}