BridJ: don't stop virtual methods search at first method with unknown name

Author: ochafik

src/main/java/org/bridj/cpp/CPPRuntime.java

@@ -509,7 +509,11 @@ public int getPositionInVirtualTable(Pointer<Pointer<?>> pVirtualTable, Method m
                 if (debug) {
                     info("\tVtable(" + className + ")[" + iVirtual + "] = null");
                 }
+            }
+            if (pMethod == null) {
                 return -1;
+            } else if (virtualMethodName == null) {
+                continue;
             }
             try {
                 MemberRef mr = library.parseSymbol(virtualMethodName);