Remove an old, seemingly out of date, comment.

The referenced script no longer seems to exist.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@192848 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Preprocessor/predefined-arch-macros.c b/test/Preprocessor/predefined-arch-macros.c
index 45e317a..af90c2d 100644
--- a/test/Preprocessor/predefined-arch-macros.c
+++ b/test/Preprocessor/predefined-arch-macros.c
@@ -1,6 +1,3 @@
-// These tests are generated by running utils/generate_arch_predefine_tests.sh
-// to observe GCC's behavior (or some other system compiler's behavior).
-//
 // Begin X86/GCC/Linux tests ----------------
 //
 // RUN: %clang -march=i386 -m32 -E -dM %s -o - 2>&1 \