[runtimes] Remove all traces of the legacy testing configuration system
Now that all jobs have moved over to the new style of Lit configuration,
we can remove all traces of the legacy testing configuration system.
This includes:
- Cache settings that are not honored or useful anymore
- Several CMake options that were only useful in the context of the
legacy Lit configuration system
- A bunch of Python support code that is not used anymore
- The legacy lit.cfg.in files themselves
Differential Revision: https://reviews.llvm.org/D134650
NOKEYCHECK=True
GitOrigin-RevId: a48f018bb7d8fadc67c08e71409c31713daa0071
diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst
index aad7dba..7a5ab32 100644
--- a/docs/ReleaseNotes.rst
+++ b/docs/ReleaseNotes.rst
@@ -72,6 +72,10 @@
incidental transitive includes more aggressively, in particular regardless
of the language version in use.
+- The legacy testing system for libc++, libc++abi and libunwind has been removed.
+ All known clients have been migrated to the new configuration system, but please
+ reach out to the libc++ developers if you find something missing in the new
+ configuration system.
Upcoming Deprecations and Removals
----------------------------------