Merge pull request swiftlang#81622 from etcwilde/ewilde/wmo-swift-testing

Build Swift-Testing with WMO

Author: etcwilde

utils/swift_build_support/swift_build_support/products/swift_testing.py

@@ -112,6 +112,8 @@ def build(self, host_target):
 
         self.cmake_options.define('CMAKE_BUILD_TYPE', self.args.build_variant)
 
+        self.cmake_options.define('CMAKE_Swift_COMPILATION_MODE', 'wholemodule')
+
         # FIXME: If we build macros for the builder, specify the path.
         self.cmake_options.define('SwiftTesting_MACRO', 'NO')