Prevent behavior change: StreamEncoder::append was NOT synchronized implicitly before, so it should NOT be synchronized explicitly now.

Author: mkarg

src/java.base/share/classes/sun/nio/cs/StreamEncoder.java

@@ -151,19 +151,15 @@ public void write(CharBuffer cb) throws IOException {
     }
 
     public Writer append(CharSequence csq) throws IOException {
-        synchronized (lock) {
-            if (csq == null) csq = "null";
-            implWrite(csq, 0, csq.length());
-            return this;
-        }
+        if (csq == null) csq = "null";
+        implWrite(csq, 0, csq.length());
+        return this;
     }
 
     public Writer append(CharSequence csq, int start, int end) throws IOException {
-        synchronized (lock) {
-            if (csq == null) csq = "null";
-            implWrite(csq, start, end - start);
-            return this;
-        }
+        if (csq == null) csq = "null";
+        implWrite(csq, start, end - start);
+        return this;
     }
 
     public void flush() throws IOException {