[libc++] Disable module_std and module_std_compat tests

Those have been crippling the CI for over a week now. This is the only
solution I see until we gain a better understanding of why they fail.
Otherwise all other patches are blocked on these spurious failures in
the stage1 of the CI.

Author: ldionne

libcxx/test/libcxx/module_std.gen.py

@@ -18,6 +18,9 @@
 
 # RUN: %{python} %s %{libcxx-dir}/utils
 
+# TODO: Re-enable this test once we understand why it keeps timing out.
+# UNSUPPORTED: clang
+
 import sys
 
 sys.path.append(sys.argv[1])

libcxx/test/libcxx/module_std_compat.gen.py

@@ -18,6 +18,9 @@
 
 # RUN: %{python} %s %{libcxx-dir}/utils
 
+# TODO: Re-enable this test once we understand why it keeps timing out.
+# UNSUPPORTED: clang
+
 import sys
 
 sys.path.append(sys.argv[1])