[libc] Fix test failing on GPU using deprecated 'add_unittest'

Summary:
We use `add_libc_test' now because it works for both hermetic and unit
tests. If the test needs to be unit test only you use `UNIT_TEST_ONLY`
as an argument.

Author: jhuber6

libc/test/include/CMakeLists.txt

@@ -1,6 +1,6 @@
 add_custom_target(libc_include_tests)
 
-add_libc_unittest(
+add_libc_test(
   sys_queue_test
   SUITE
     libc_include_tests