Fix: linker segfault on dlopen of a DF_1_GLOBAL so

Added the missing null check routine.

Bug: 67755729
Test: dlfcn.dlopen_df_1_global added and it passes
Change-Id: Ibe8db18b0b5a481e2e9937041abef6d6b179dd87
diff --git a/tests/dlfcn_test.cpp b/tests/dlfcn_test.cpp
index adc5ee4..697b84a 100644
--- a/tests/dlfcn_test.cpp
+++ b/tests/dlfcn_test.cpp
@@ -1496,4 +1496,9 @@
   ASSERT_SUBSTR(expected_dlerror.c_str(), dlerror());
 }
 
+TEST(dlfcn, dlopen_df_1_global) {
+  void* handle = dlopen("libtest_dlopen_df_1_global.so", RTLD_NOW);
+  ASSERT_TRUE(handle != nullptr) << dlerror();
+}
+
 #endif