Fix failing test (#4392)

#### PR checklist

- [X] Addresses an existing issue: #4391 

#### Overview of change:

Fix test that failed locally because it took too long. Not sure why this is only becoming an issue now - could be something that got added, but for now we may as well get 5.12 released and then figure it out.

test/executable/executableTests.ts

@@ -39,7 +39,7 @@ const dummyLogger: Logger = {
 
 describe("Executable", function(this: Mocha.ISuiteCallbackContext) {
     this.slow(3000); // the executable is JIT-ed each time it runs; avoid showing slowness warnings
-    this.timeout(4000);
+    this.timeout(10000);
 
     describe("Files", () => {
         it("exits with code 1 if no arguments passed", done => {