Canonicalize the attribute list when printing a LazyTensorOperation

Author: bgogul

Sources/TensorFlow/Core/LazyTensorOperation.swift

@@ -687,7 +687,7 @@ extension LazyTensor: CustomStringConvertible {
 
 extension LazyTensorOperation: CustomStringConvertible {
     public var description: String {
-        let attrsDesc = attrs.map { (name, value) in "\(name): \(value)" }
+        let attrsDesc = attrs.keys.sorted(by: <).map { "\($0): \(attrs[$0]!)" }
         let inputsDesc = inputs.map { (input: Input) -> String in
             switch input {
             case Input.single(let lazyTensor):

Tests/TensorFlowTests/LazyTensorOperationTests.swift

@@ -166,10 +166,7 @@ final class LazyTensorOperationTests: XCTestCase {
             _id: "0", name: "Nop", outputCount: 1)
         op0.updateAttribute("b", true)
         op0.updateAttribute("s", "hello")
-        XCTAssert(
-            (op0.description == "%0 = Nop[b: true, s: \"hello\"]()") ||
-            (op0.description == "%0 = Nop[s: \"hello\", b: true]()")
-        )
+        XCTAssertEqual(op0.description, "%0 = Nop[b: true, s: \"hello\"]()")
     }
 
     func testFunctionAttribute() {