[lldb] Import ObjectiveC module instead of Foundation in test

Use `@import ObjectiveC` instead of `@import Foundation`, as the former is all
that's needed, and results in fewer clang modules being built.

This results in the following clang modules *not* being built for this test.

ApplicationServices
CFNetwork
ColorSync
CoreFoundation
CoreGraphics
CoreServices
CoreText
DiskArbitration
Dispatch
Foundation
IOKit
ImageIO
Security
XPC
_Builtin_intrinsics
launch
libkern
os_object
os_workgroup

Differential Revision: https://reviews.llvm.org/D99859

GitOrigin-RevId: 10ed479d7303af7c6e2528185c7e7cd318c9172c
diff --git a/test/API/lang/objc/modules-app-update/TestClangModulesAppUpdate.py b/test/API/lang/objc/modules-app-update/TestClangModulesAppUpdate.py
index 29c4872..45870e8 100644
--- a/test/API/lang/objc/modules-app-update/TestClangModulesAppUpdate.py
+++ b/test/API/lang/objc/modules-app-update/TestClangModulesAppUpdate.py
@@ -20,7 +20,7 @@
                     """)
         with open(self.getBuildArtifact("f.h"), "w") as f:
             f.write("""
-                    @import Foundation;
+                    @import ObjectiveC;
                     @interface Foo : NSObject {
                        int i;
                     }
diff --git a/test/API/lang/objc/modules-app-update/foo.m b/test/API/lang/objc/modules-app-update/foo.m
index 83a5abc..f9f244c 100644
--- a/test/API/lang/objc/modules-app-update/foo.m
+++ b/test/API/lang/objc/modules-app-update/foo.m
@@ -1,4 +1,4 @@
-@import Foundation;
+@import ObjectiveC;
 @import Foo;
 @implementation Foo
 +(instancetype)init {