test: fix typo in windows test configuration

Fix a silly typo that I missed during the last synchronisation across Windows to
Linux.

Author: compnerd

test/lit.cfg

@@ -846,7 +846,7 @@ elif run_os in ['windows-msvc']:
     config.target_swift_ide_test =                                               \
             ('%r -target %s %s %s %s' % (config.swift_ide_test,                  \
                                          config.variant_triple,                  \
-                                         resource_dir_opt, pcp_opt, ccp_opt))
+                                         resource_dir_opt, mcp_opt, ccp_opt))
 
     subst_target_swift_ide_test_mock_sdk = config.target_swift_ide_test
     subst_target_swift_ide_test_mock_sdk_after = ''