Merge from vscode 011858832762aaff245b2336fb1c38166e7a10fb (#4663)

src/vs/platform/keybinding/test/common/keybindingResolver.test.ts

@@ -26,7 +26,7 @@ suite('KeybindingResolver', () => {
 			resolvedKeybinding,
 			command,
 			commandArgs,
-			when ? when.normalize() : null,
+			when ? when.normalize() : undefined,
 			isDefault
 		);
 	}