fix(decdk): set the timeout in the schema tests to 10 seconds. (#2250)

Author: skinny85

packages/decdk/test/schema.test.ts

@@ -9,6 +9,9 @@ const fixturedir = path.join(__dirname, 'fixture');
 
 // tslint:disable:no-console
 
+// JSII often does not complete in the default 5 second Jest timeout
+jest.setTimeout(10_000);
+
 let typesys: reflect.TypeSystem;
 
 beforeAll(async () => {