[libunwind] [test] Mark the signal_frame test as unsupported on Windows

Mark it as unsupported on x86_64, arm and aarch64. On i686, DWARF
is used as the default unwinding format, and there, the CFI
directives are supported.

Differential Revision: https://reviews.llvm.org/D147858

GitOrigin-RevId: 11ed806e7fdb1df74bba727165e68d675bbaa5e1
diff --git a/test/signal_frame.pass.cpp b/test/signal_frame.pass.cpp
index 482481d..e5409f6 100644
--- a/test/signal_frame.pass.cpp
+++ b/test/signal_frame.pass.cpp
@@ -21,6 +21,10 @@
 // are necessary to run this test.
 // UNSUPPORTED: target=powerpc{{(64)?}}-ibm-aix
 
+// Windows doesn't generally use CFI directives. However, i686
+// mingw targets do use DWARF (where CFI directives are supported).
+// UNSUPPORTED: target={{x86_64|arm.*|aarch64}}-{{.*}}-windows-{{.*}}
+
 #undef NDEBUG
 #include <assert.h>
 #include <stdlib.h>