JSSE: fix deadlock issues between SSLSocket close() and OutputStream write()

[cconlon]

This PR fixes a few deadlock issues that could occur between SSLSocket.close() and the associated SSLSocket's OutputStream.write().

Originally from user report of deadlock, was similar to:

Thread 1:
    at com.wolfssl.provider.jsse.WolfSSLSocket$WolfSSLOutputStream.close(WolfSSLSocket.java:2618)
    - waiting to lock <0x00000000f42874f8> (a com.wolfssl.provider.jsse.WolfSSLSocket$WolfSSLOutputStream)
    at com.wolfssl.provider.jsse.WolfSSLSocket.close(WolfSSLSocket.java:1951)
    - locked <0x00000000f4287588> (a java.lang.Object)
    - locked <0x00000000f4287578> (a java.lang.Object)
    - locked <0x00000000f4287518> (a com.wolfssl.provider.jsse.WolfSSLSocket)

Thread 2:
    at com.wolfssl.provider.jsse.WolfSSLSocket$WolfSSLOutputStream.write(WolfSSLSocket.java:2684)
    - waiting to lock <0x00000000f4287588> (a java.lang.Object)
    - locked <0x00000000f42874f8> (a com.wolfssl.provider.jsse.WolfSSLSocket$WolfSSLOutputStream)

Similar deadlock was observed when running against SunJSSE test SSLSocketImpl/AsyncSSLSocketClose.java:

Java stack information for the threads listed above:
===================================================
"Thread-1":
    at java.net.Socket.getSoTimeout(Socket.java:1174)
    - waiting to lock <0x000000066bdd0908> (a com.wolfssl.provider.jsse.WolfSSLSocket)
    at com.wolfssl.provider.jsse.WolfSSLSocket.getSoTimeout(WolfSSLSocket.java:1860)
    at com.wolfssl.provider.jsse.WolfSSLSocket$WolfSSLOutputStream.write(WolfSSLSocket.java:2869)
    - locked <0x000000066c4bf330> (a com.wolfssl.provider.jsse.WolfSSLSocket$WolfSSLOutputStream)
    at com.wolfssl.provider.jsse.WolfSSLSocket$WolfSSLOutputStream.write(WolfSSLSocket.java:2793)
    at AsyncSSLSocketClose.run(AsyncSSLSocketClose.java:124)
    at java.lang.Thread.run(Thread.java:750)
"MainThread":
    at com.wolfssl.provider.jsse.WolfSSLSocket$WolfSSLOutputStream.close(WolfSSLSocket.java:2739)
    - waiting to lock <0x000000066c4bf330> (a com.wolfssl.provider.jsse.WolfSSLSocket$WolfSSLOutputStream)
    at com.wolfssl.provider.jsse.WolfSSLSocket.close(WolfSSLSocket.java:2074)
    - locked <0x000000066bdd0908> (a com.wolfssl.provider.jsse.WolfSSLSocket)
    at AsyncSSLSocketClose.<init>(AsyncSSLSocketClose.java:95)
    at AsyncSSLSocketClose.main(AsyncSSLSocketClose.java:69)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
    at java.lang.Thread.run(Thread.java:750)

Found 1 deadlock.