Fix for linker allocator

Change-Id: I18a3f1a8515657f0deb69266184fb516a27f90e8
diff --git a/linker/tests/linker_allocator_test.cpp b/linker/tests/linker_allocator_test.cpp
index e3a91c5..0ed8252 100644
--- a/linker/tests/linker_allocator_test.cpp
+++ b/linker/tests/linker_allocator_test.cpp
@@ -96,6 +96,9 @@
     ASSERT_TRUE(allocator.alloc() != nullptr);
   }
 
+  test_struct_larger* ptr_to_free = allocator.alloc();
+  ASSERT_TRUE(ptr_to_free != nullptr);
+  allocator.free(ptr1);
 }
 
 static void protect_all() {