Fix a memory leak in Error objects

https://crbug.com/v8/7142

packages/jest-circus/src/index.js

@@ -29,8 +29,16 @@ describe.skip = (blockName: BlockName, blockFn: BlockFn) =>
   _dispatchDescribe(blockFn, blockName, 'skip');
 
 const _dispatchDescribe = (blockFn, blockName, mode?: BlockMode) => {
+  const asyncError = new Error();
+
+  // Without this line v8 stores references to all closures
+  // in the stack in the Error object. This line stringifies the stack
+  // property to allow garbage-collecting objects on the stack
+  // https://crbug.com/v8/7142
+  asyncError.stack = asyncError.stack;
+
   dispatch({
-    asyncError: new Error(),
+    asyncError,
     blockName,
     mode,
     name: 'start_describe_definition',
@@ -48,6 +56,13 @@ const _addHook = (fn: HookFn, hookType: HookType, hookFn, timeout: ?number) => {
   if (Error.captureStackTrace) {
     Error.captureStackTrace(asyncError, hookFn);
   }
+
+  // Without this line v8 stores references to all closures
+  // in the stack in the Error object. This line stringifies the stack
+  // property to allow garbage-collecting objects on the stack
+  // https://crbug.com/v8/7142
+  asyncError.stack = asyncError.stack;
+
   dispatch({asyncError, fn, hookType, name: 'add_hook', timeout});
 };
 
@@ -81,6 +96,12 @@ const test = (testName: TestName, fn: TestFn, timeout?: number) => {
     Error.captureStackTrace(asyncError, test);
   }
 
+  // Without this line v8 stores references to all closures
+  // in the stack in the Error object. This line stringifies the stack
+  // property to allow garbage-collecting objects on the stack
+  // https://crbug.com/v8/7142
+  asyncError.stack = asyncError.stack;
+
   return dispatch({
     asyncError,
     fn,
@@ -96,6 +117,12 @@ test.skip = (testName: TestName, fn?: TestFn, timeout?: number) => {
     Error.captureStackTrace(asyncError, test);
   }
 
+  // Without this line v8 stores references to all closures
+  // in the stack in the Error object. This line stringifies the stack
+  // property to allow garbage-collecting objects on the stack
+  // https://crbug.com/v8/7142
+  asyncError.stack = asyncError.stack;
+
   return dispatch({
     asyncError,
     fn,
@@ -111,6 +138,12 @@ test.only = (testName: TestName, fn: TestFn, timeout?: number) => {
     Error.captureStackTrace(asyncError, test);
   }
 
+  // Without this line v8 stores references to all closures
+  // in the stack in the Error object. This line stringifies the stack
+  // property to allow garbage-collecting objects on the stack
+  // https://crbug.com/v8/7142
+  asyncError.stack = asyncError.stack;
+
   return dispatch({
     asyncError,
     fn,