[NFC] Add a test case for SR-12365

Author: hborla

test/Constraints/sr12365.swift

@@ -0,0 +1,23 @@
+// RUN: %target-swift-frontend -typecheck -verify %s
+
+public protocol MyProtocol {}
+
+public struct MyProtocolImpl: MyProtocol {}
+
+public func != (lhs: MyProtocol, rhs: MyProtocol) -> MyProtocolImpl {
+  return MyProtocolImpl()
+}
+
+public func && (lhs: MyProtocol, rhs: MyProtocol) -> MyProtocolImpl {
+  return MyProtocolImpl()
+}
+
+func check(a: Double, b: Int64) -> Bool {
+  return a != 0 && b != 0 // Okay
+}
+
+func check() {
+  let x: Int = 1
+  let _ = UInt(1) << x - 1 // Okay
+  let _ = UInt(1) << (x + 1) - 1 // Okay
+}