Remove unused variable in xcode_locator.m

Closes #6453.

PiperOrigin-RevId: 218415299
diff --git a/tools/osx/xcode_locator.m b/tools/osx/xcode_locator.m
index cd44267..6e318d7 100644
--- a/tools/osx/xcode_locator.m
+++ b/tools/osx/xcode_locator.m
@@ -191,8 +191,6 @@
 static void DumpAsVersionsOnly(
   FILE *output,
   NSMutableDictionary<NSString *, XcodeVersionEntry *> *dict) {
-  NSSet<XcodeVersionEntry *> *distinctValues =
-      [[NSSet alloc] initWithArray:dict.allValues];
   NSMutableDictionary<NSString *, NSMutableSet <NSString *> *> *aliasDict =
       [[NSMutableDictionary alloc] init];
   [dict enumerateKeysAndObjectsUsingBlock:^(NSString *aliasVersion,