[lldb][test] Explain why TestExprFromNonZeroFrame is disabled on Windows

It's not scientific but I think the PDB we produce on the Windows on Arm
bot simply doesn't have the information needed. Could also be that clang
is producing some DWARF, but link.exe is dropping it from the final executable,
the effect is the same.

Author: DavidSpickett

lldb/test/API/commands/expression/expr-from-non-zero-frame/TestExprFromNonZeroFrame.py

@@ -7,7 +7,7 @@
 class ExprFromNonZeroFrame(TestBase):
     NO_DEBUG_INFO_TESTCASE = True
 
-    # Expression fails to evaluate on Windows, for unknown reasons.
+    # Requires DWARF debug information.
     @skipIfWindows
     def test(self):
         """