Add xcode_locator to bazel's embedded binaries.
For bazel on non-darwin architectures, this will simply be a stub, and should never be invoked. On darwin arcitectures, the tool will map xcode version to xcode path on the host system.

--
MOS_MIGRATED_REVID=111651147

src/test/java/com/google/devtools/build/lib/testutil/TestConstants.java

diff --git a/src/test/java/com/google/devtools/build/lib/testutil/TestConstants.java b/src/test/java/com/google/devtools/build/lib/testutil/TestConstants.java
index 701487f..96bcfca 100644
--- a/src/test/java/com/google/devtools/build/lib/testutil/TestConstants.java
+++ b/src/test/java/com/google/devtools/build/lib/testutil/TestConstants.java
@@ -30,7 +30,8 @@
       "build_interface_so",
       "build-runfiles",
       "namespace-sandbox",
-      "process-wrapper");
+      "process-wrapper",
+      "xcode-locator");
 
   /**
    * Location in the bazel repo where embedded binaries come from.