[lldb][test] Skip platform attach test on Windows

This can pass but every so often times out:
https://lab.llvm.org/buildbot/#/builders/219/builds/6092

Author: DavidSpickett

lldb/test/API/functionalities/gdb_remote_client/TestPlatformAttach.py

@@ -7,6 +7,7 @@
 
 class TestPlatformAttach(GDBRemoteTestBase):
     @skipIfRemote
+    @skipIfWindows
     def test_attach(self):
         """Test attaching by name"""