Use HttpResponse constructor in protocol tests

Updates the TS protocol test stub to construct HttpResponse objects
using the class constructor, instead of with object syntax. The
constructor has optional parameters, so when updating the HttpResponse
implementation we can continue to pass old properties. Without using
the constructor, we have to change the HttpResponse interface and
protocol test codegen simulataneously to avoid breaking changes.

Author: milesziemer

smithy-typescript-codegen/src/main/resources/software/amazon/smithy/typescript/codegen/protocol-test-stub.ts

@@ -57,11 +57,11 @@ class ResponseDeserializationTestHandler implements HttpHandler {
         options?: HttpHandlerOptions
     ): Promise<{ response: HttpResponse }> {
         return Promise.resolve({
-            response: {
+            response: new HttpResponse({
                 statusCode: this.code,
                 headers: this.headers,
                 body: Readable.from([this.body])
-            }
+            })
         });
     }
 }