AST: Only need 1 bit to store ModuleDecl's resilience strategy

Author: slavapestov

include/swift/AST/Module.h

@@ -206,7 +206,7 @@ class ModuleDecl : public DeclContext, public TypeDecl {
   struct {
     unsigned TestingEnabled : 1;
     unsigned FailedToLoad : 1;
-    unsigned ResilienceStrategy : 2;
+    unsigned ResilienceStrategy : 1;
   } Flags;
 
   ModuleDecl(Identifier name, ASTContext &ctx);