Sort tests by path before before distributing to nodes

The `tests` parameter may not be sorted in the same way across nodes,
so we need to sort them first before distributing the tests.

scripts/frontend/parallel_ci_sequencer.js

@@ -8,14 +8,27 @@ class ParallelCISequencer extends Sequencer {
   }
 
   sort(tests) {
-    const testsForThisRunner = this.distributeAcrossCINodes(tests);
+    const sortedTests = this.sortByPath(tests);
+    const testsForThisRunner = this.distributeAcrossCINodes(sortedTests);
 
     console.log(`CI_NODE_INDEX: ${this.ciNodeIndex}`);
     console.log(`CI_NODE_TOTAL: ${this.ciNodeTotal}`);
     console.log(`Total number of tests: ${tests.length}`);
     console.log(`Total number of tests for this runner: ${testsForThisRunner.length}`);
 
-    return super.sort(testsForThisRunner);
+    return testsForThisRunner;
+  }
+
+  sortByPath(tests) {
+    return tests.sort((test1, test2) => {
+      if (test1.path < test2.path) {
+        return -1;
+      }
+      if (test1.path > test2.path) {
+        return 1;
+      }
+      return 0;
+    });
   }
 
   distributeAcrossCINodes(tests) {