InputStreamMonitor.writeNext() wait() not in loop — vulnerable to spurious wakeups

In `InputStreamMonitor.writeNext()`, the `fLock.wait()` call at line 189 is guarded by an `if` check:

```java
synchronized(fLock) {
// Queue could receive more input between last empty check and
// lock acquire. See https://bugs.eclipse.org/550834
if (fQueue.isEmpty()) {
fLock.wait();
}
}
```

Per the [Java specification](https://docs.oracle.com/javase/specs/jls/se17/html/jls-17.html#jls-17.2.1), `Object.wait()` can return spuriously — without a corresponding `notify()`/`notifyAll()`. The standard pattern is to use a `while` loop instead of `if`:

```java
synchronized(fLock) {
while (fQueue.isEmpty() && !fClosed) {
fLock.wait();
}
}
```

This ensures the condition is rechecked after any wakeup. The `!fClosed` guard also avoids waiting forever if the stream was closed while waiting.

Found via SpotBugs static analysis (WA_NOT_IN_LOOP).

Start at InputStreamMonitor.writeNext() around line 189 and inspect the surrounding queue and stream-close handling. Check the SpotBugs WA_NOT_IN_LOOP finding, then verify that wakeups recheck the queue and that a closed stream cannot wait forever.

Written by the indexing model from the issue text.