[lldb] [testsuite] Mark TestSBCommandReturnObject as failing on Windows

Filed:
	testsuite: TestSBCommandReturnObject: object has no attribute 'dylibPath'
	https://bugs.llvm.org/show_bug.cgi?id=43570

http://lab.llvm.org:8011/builders/lldb-x64-windows-ninja/builds/9530/steps/test/logs/stdio

AttributeError: 'TestSBCommandReturnObject' object has no attribute 'dylibPath'

Fix crash on SBCommandReturnObject & assignment
https://reviews.llvm.org/D67589
  env = {self.dylibPath: self.getLLDBLibraryEnvVal()}

I do not know how to link with liblldb on Windows so marking it as failing on
Windows.

llvm-svn: 373787