test: remove target macro for Windows

The target is now specified by the frontend so we do not need to specify
the target manually.

Author: compnerd

test/lit.cfg

@@ -338,10 +338,6 @@ swift_version = lit_config.params.get('swift-version',
 lit_config.note('Compiling with -swift-version ' + swift_version)
 config.swift_test_options = '-swift-version ' + swift_version
 
-if run_os == 'windows-msvc':
-  if run_cpu == 'x86_64':
-    config.swift_test_options += ' -Xcc -D_AMD64_'
-
 test_options = os.environ.get('SWIFT_TEST_OPTIONS')
 if test_options:
     config.swift_test_options += ' '