Mark $implicit_tests attribute from test_suite as order independent.

--
MOS_MIGRATED_REVID=102294171
diff --git a/src/main/java/com/google/devtools/build/lib/packages/Package.java b/src/main/java/com/google/devtools/build/lib/packages/Package.java
index 28681d4..1cd3635 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/Package.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/Package.java
@@ -1287,6 +1287,7 @@
           allTests.add(rule.getLabel());
         }
       }
+      Collections.sort(allTests);
       for (Rule rule : rules) {
         AttributeMap attributes = NonconfigurableAttributeMapper.of(rule);
         if (rule.getRuleClass().equals("test_suite")