Rename the <grp.h>/<pwd.h> tests to reflect that they're no longer in stubs.cpp.

Bug: http://b/27999086
Change-Id: I3255ad5861a705beeb9b462e22f79ae1e5a85a79
diff --git a/tests/Android.mk b/tests/Android.mk
index 7fdf2f4..c190428 100644
--- a/tests/Android.mk
+++ b/tests/Android.mk
@@ -60,6 +60,7 @@
     ftw_test.cpp \
     getauxval_test.cpp \
     getcwd_test.cpp \
+    grp_pwd_test.cpp \
     ifaddrs_test.cpp \
     inttypes_test.cpp \
     libc_logging_test.cpp \
@@ -95,7 +96,6 @@
     string_posix_strerror_r_test.cpp \
     strings_nofortify_test.cpp \
     strings_test.cpp \
-    stubs_test.cpp \
     sstream_test.cpp \
     sys_epoll_test.cpp \
     sys_mman_test.cpp \