[moveOnly] Add a feature for BuiltinMove that we can use to prevent cond_fail errors.

We use it in a subsequent commit in this PR to guard BuiltinMove.

Author: gottesmm

include/swift/Basic/Features.def

@@ -54,5 +54,6 @@ LANGUAGE_FEATURE(ImplicitSelfCapture, 0, "@_implicitSelfCapture attribute", true
 LANGUAGE_FEATURE(BuiltinBuildExecutor, 0, "Executor-building builtins", true)
 LANGUAGE_FEATURE(BuiltinBuildMainExecutor, 0, "MainActor executor building builtin", true)
 LANGUAGE_FEATURE(BuiltinCreateAsyncTaskInGroup, 0, "MainActor executor building builtin", true)
+LANGUAGE_FEATURE(BuiltinMove, 0, "Builtin.move()", true)
 
 #undef LANGUAGE_FEATURE

lib/AST/ASTPrinter.cpp

@@ -2812,6 +2812,10 @@ static bool usesFeatureBuiltinCreateAsyncTaskInGroup(Decl *decl) {
   return false;
 }
 
+static bool usesFeatureBuiltinMove(Decl *decl) {
+  return false;
+}
+
 static bool usesFeatureInheritActorContext(Decl *decl) {
   if (auto func = dyn_cast<AbstractFunctionDecl>(decl)) {
     for (auto param : *func->getParameters()) {