JDK-8320005 : Allow loading of shared objects with .a extension on AIX

src/hotspot/os/aix/os_aix.cpp

@@ -1175,6 +1175,7 @@
   char* const pointer_to_dot = strrchr(file_path, '.');
   if (pointer_to_dot == nullptr) {
     log_info(os)("Attempting to load a shared object without extension %s", filename);
+    return result;
   }    
   // First try to load the existing file.
   result = dll_load_library(file_path, ebuf, ebuflen);
@@ -1195,7 +1196,7 @@
 }
 
 void os::get_summary_os_info(char* buf, size_t buflen) {
   // There might be something more readable than uname results for AIX.
   struct utsname name;
   uname(&name);
   snprintf(buf, buflen, "%s %s", name.release, name.version);