test: Skip failure on FreeBSD from test infrastructure issue

test_convenience_registers_16bit_with_process_attach fails due to
pr18200.  The test has a @expectedFailureFreeBSD decorator, but it
appears this does not catch a RuntimError exception raised in the test
infrastructure, so the test still reports failure.  For now just skip
it.

llvm-svn: 197174

lldb/test/functionalities/register/TestRegisters.py

@@ -53,6 +53,7 @@ class RegisterCommandsTestCase(TestBase):
         self.buildDefault()
         self.convenience_registers_with_process_attach(test_16bit_regs=False)
 
+    @skipIfFreeBSD # llvm.org/pr18230
     @expectedFailureFreeBSD("llvm.org/pr18200")
     def test_convenience_registers_16bit_with_process_attach(self):
         """Test convenience registers after a 'process attach'."""