[clang] [clang][rtsan] Introduce realtime sanitizer codegen and driver (PR #102622)

[Chris Apple via cfe-commits]

================
@@ -0,0 +1,14 @@
+// RUN: %clang     -target x86_64-unknown-linux -fsanitize=realtime %s -S -emit-llvm -o - | FileCheck %s
----------------
cjappl wrote:

The basis of this test file were very similar ones for asan and tsan:
https://github.com/llvm/llvm-project/blob/main/clang/test/Driver/tsan.c
https://github.com/llvm/llvm-project/blob/main/clang/test/Driver/asan.c

So I thought it was required for rtsan as well! Do you recommend I delete this test, or move it elsewhere? I defer to your expertise.

 I will fix the tests in Codegen to use clang_cc1

https://github.com/llvm/llvm-project/pull/102622