[llvm] [outliners] Turn nooutline into an Enum Attribute (PR #163665)

[Sam Elliott via llvm-commits]

================
@@ -0,0 +1,12 @@
+; RUN: llvm-as < %s | llvm-dis - | FileCheck %s
+
+; CHECK: define void @f() [[ATTR:#[0-9]+]]
----------------
lenary wrote:

I switched to `--implicit-check-not`.

https://github.com/llvm/llvm-project/pull/163665