Fix aafwk testcases on master branch 20210526.

Change-Id: Ief4dd4d71b1d8ea4894c88133c548e29d4e2a805

aafwk_lite/ability_posix/BUILD.gn

@@ -71,5 +71,6 @@ hcpptest_suite("ActsAbilityMgrTest") {
     "-lstdc++",
     "-lm",
     "-lpthread",
+    "-ldl",
   ]
 }