[runtimes][ci] Run the tests for libunwind in the CI

We should arguably have always been doing that. The state of libunwind
is quite sad, so this commit adds several XFAILs to make the CI pass.
We need to investigate why so many tests are not passing in some
configurations, but I'll defer that to folks who actually work on
libunwind for lack of bandwidth.

Differential Revision: https://reviews.llvm.org/D110872

NOKEYCHECK=True
GitOrigin-RevId: 60fe1f59d08b815a280761e625d12a74a501f444
diff --git a/test/signal_frame.pass.cpp b/test/signal_frame.pass.cpp
index 28f8d99..fea1897 100644
--- a/test/signal_frame.pass.cpp
+++ b/test/signal_frame.pass.cpp
@@ -9,6 +9,15 @@
 
 // Ensure that functions marked as signal frames are reported as such.
 
+// TODO: Investigate these failures
+// XFAIL: asan, tsan, ubsan
+
+// TODO: Investigate this failure on macOS
+// XFAIL: target={{.+}}-apple-darwin{{.+}}
+
+// TODO: Investigate this failure
+// XFAIL: 32bits-on-64bits
+
 // UNSUPPORTED: libunwind-arm-ehabi
 
 #include <assert.h>