8215243: JShell tests failing intermitently with \"Problem cleaning up the following threads:\"

Do not reset closed state in the StopDetectingInputStream.write

Reviewed-by: rfield

src/jdk.jshell/share/classes/jdk/internal/jshell/tool/StopDetectingInputStream.java

@@ -113,7 +113,7 @@ public final class StopDetectingInputStream extends InputStream {
     }
 
     public synchronized void write(int b) {
-        if (state != State.BUFFER) {
+        if (state == State.READ) {
             state = State.WAIT;
         }
         int newEnd = (end + 1) % buffer.length;