[lldb][test] Disable DeclFromSubmodule test on Windows

Or more precisely, when linking with link.exe, but Windows
is our closest proxy for that right now.

This test requires the DWARF info to work, on the Windows on Arm
buildbot it fails:
```
AssertionError: Ran command:
"expr func(1, 2)"

Got output:
error: <user expression 0>:1:1: use of undeclared identifier 'func'

    1 | func(1, 2)

      | ^~~~

Expecting start string: "error: <user expression 0>:1:1: 'func' has unknown return type" (was not found)
```

Author: DavidSpickett

lldb/test/API/lang/cpp/decl-from-submodule/TestDeclFromSubmodule.py

@@ -9,6 +9,8 @@
 
 
 class DeclFromSubmoduleTestCase(TestBase):
+    # Requires DWARF debug info which is not retained when linking with link.exe.
+    @skipIfWindows
     def test_expr(self):
         self.build()
         lldbutil.run_to_source_breakpoint(self, "return 0", lldb.SBFileSpec("main.cpp"))