Remove workaround for old glibc sysroot.

Bug: http://b/374104004
Change-Id: Icdde8258b97ffcafdbb4cefc03fc8187703fb982
diff --git a/tests/headers/posix/stdatomic_h.c b/tests/headers/posix/stdatomic_h.c
index 05be859..eecb89a 100644
--- a/tests/headers/posix/stdatomic_h.c
+++ b/tests/headers/posix/stdatomic_h.c
@@ -93,10 +93,7 @@
   atomic_flag f = ATOMIC_FLAG_INIT;
   atomic_int i = ATOMIC_VAR_INIT(123);
 
-  // TODO: remove this #if after the next toolchain update (http://b/374104004).
-#if !defined(__GLIBC__)
   i = kill_dependency(i);
-#endif
 
 #if !defined(atomic_compare_exchange_strong)
 #error atomic_compare_exchange_strong