cpplint: Cleanup errors

Cleanup errors from upstream cpplint in preparation
for moving art's cpplint fork to upstream tip-of-tree cpplint.

Test: cd art && mm
Bug: 68951293
Change-Id: I15faed4594cbcb8399850f8bdee39d42c0c5b956
diff --git a/compiler/optimizing/scheduler.h b/compiler/optimizing/scheduler.h
index afdf6f1..a6e1603 100644
--- a/compiler/optimizing/scheduler.h
+++ b/compiler/optimizing/scheduler.h
@@ -392,7 +392,7 @@
  */
 class RandomSchedulingNodeSelector : public SchedulingNodeSelector {
  public:
-  explicit RandomSchedulingNodeSelector() : seed_(0) {
+  RandomSchedulingNodeSelector() : seed_(0) {
     seed_  = static_cast<uint32_t>(NanoTime());
     srand(seed_);
   }