Support Xcode betas with xcode-locator

Previously if you had 2 builds of the same version of Xcode, for example
10.2.0 beta 1 and 10.2.0 beta 2, there was no way to disambiguate them.
This change appends the `CFBundleVersion` of each Xcode version to allow
you to specify that if desired.

tools/osx/xcode_locator.m

@@ -64,10 +64,14 @@ - (id)description {
 // 2. Not older (at least as high version number).
 static void AddEntryToDictionary(
   XcodeVersionEntry *entry,
+  NSString *bundleVersion,
   NSMutableDictionary<NSString *, XcodeVersionEntry *> *dict) {
   BOOL inApplications =
       [entry.url.path rangeOfString:@"/Applications/"].location != NSNotFound;
   NSString *entryVersion = entry.version;
+  if (bundleVersion) {
+    entryVersion = [entryVersion stringByAppendingFormat:@".%@", bundleVersion];
+  }
   NSString *subversion = entryVersion;
   if (dict[entryVersion] && !inApplications) {
     return;
@@ -172,16 +176,19 @@ static void AddEntryToDictionary(
       errors = YES;
       continue;
     }
+
     NSString *expandedVersion = ExpandVersion(version);
     NSLog(@"Version strings for %@: short=%@, expanded=%@",
           url, version, expandedVersion);
 
+    NSString *bundleVersion = [bundle.infoDictionary
+        objectForKey:@"CFBundleVersion"];
     NSURL *developerDir =
         [url URLByAppendingPathComponent:@"Contents/Developer"];
     XcodeVersionEntry *entry =
         [[XcodeVersionEntry alloc] initWithVersion:expandedVersion
                                                url:developerDir];
-    AddEntryToDictionary(entry, dict);
+    AddEntryToDictionary(entry, bundleVersion, dict);
   }
   return errors ? nil : dict;
 }