[runtimes] Simplify how we specify XFAIL & friends based on the triple

Now that Lit supports regular expressions inside XFAIL & friends, it is
much easier to write Lit annotations based on the triple.

Differential Revision: https://reviews.llvm.org/D104747

NOKEYCHECK=True
GitOrigin-RevId: c360553c15a8e5aa94d2236eb73e7dfeab9543e5
diff --git a/test/signal_unwind.pass.cpp b/test/signal_unwind.pass.cpp
index 3acd772..c16adeb 100644
--- a/test/signal_unwind.pass.cpp
+++ b/test/signal_unwind.pass.cpp
@@ -8,7 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 // Ensure that the unwinder can cope with the signal handler.
-// REQUIRES: linux && (target-aarch64 || target-x86_64)
+// REQUIRES: linux && (target={{aarch64-.+}} || target={{x86_64-.+}})
 
 #include <assert.h>
 #include <dlfcn.h>