test: unflake async-hooks/test-statwatcher

On Windows 2016 under high load further change events can be emitted
after writing the 5 bytes is reported. Updating the mtime of the file
can be reported as a separate change. This will increase the "before"
count, but not the "w1HookCount" since we removed the listener.

This makes the test keep the listeners until the end of the test.

Fixes: nodejs#21425

test/async-hooks/async-hooks.status

@@ -7,8 +7,6 @@ prefix async-hooks
 [true] # This section applies to all platforms
 
 [$system==win32]
-# https://github.com/nodejs/node/issues/29852
-test-statwatcher: PASS,FLAKY
 
 [$system==linux]
 

test/async-hooks/test-statwatcher.js

@@ -64,8 +64,6 @@ w1.on('change', common.mustCallAtLeast((curr, prev) => {
   // Wait until we get the write above.
   if (prev.size !== 0 || curr.size !== 5)
     return;
-  // Remove listeners to make w1HookCount final
-  w1.removeAllListeners('change');
 
   setImmediate(() => {
     checkInvocations(statwatcher1,
@@ -81,8 +79,6 @@ w1.on('change', common.mustCallAtLeast((curr, prev) => {
       // Wait until we get the write above.
       if (prev.size !== 0 || curr.size !== 5)
         return;
-      // Remove listeners to make w2HookCount final
-      w2.removeAllListeners('change');
 
       setImmediate(() => {
         checkInvocations(statwatcher1,