[NFC][AIX] Disable precompiled module file test on AIX

[Jake-Egan]

Summary

This patch follows the same reasoning as D114481. The PCH reader looks for __clangast section in the precompiled module file, which is not present in the file on AIX and not supported in XCOFF yet.

[daltenty]

LGTM, thanks!

clang/test/ClangScanDeps/modules-no-undeclared-includes.c

+// Unsupported on AIX because we don't support the requisite "__clangast"
+// section in XCOFF yet.
+// UNSUPPORTED: aix
+
 // RUN: rm -rf %t && mkdir %t
 // RUN: split-file %s %t
 
 //--- undeclared/module.modulemap
 module Undeclared { header "undeclared.h" }
 
 //--- undeclared/undeclared.h