[lldb] Replace unneeded use of Foundation with ObjectiveC in tests (NFC)

When referencing `NSObject`, it's enough to import `objc/NSObject.h`. Importing `Foundation` is unnecessary in these cases.

Differential Revision: https://reviews.llvm.org/D99867

lldb/test/API/python_api/class_members/main.mm

@@ -1,4 +1,4 @@
-#import <Foundation/Foundation.h>
+#import <objc/NSObject.h>
 
 class Base {
 public:

lldb/test/API/python_api/objc_type/Makefile

@@ -1,8 +1,5 @@
 OBJC_SOURCES := main.m
-
 CFLAGS_EXTRAS := -w
+LD_EXTRAS := -lobjc
 
-
-
-LD_EXTRAS := -framework Foundation
 include Makefile.rules

lldb/test/API/python_api/objc_type/main.m

@@ -1,4 +1,4 @@
-#import <Foundation/Foundation.h>
+#import <objc/NSObject.h>
 
 @interface Foo: NSObject
 {}