Fix newly discovered presubmit errors.

src/arm64/lithium-arm64.h

Index: src/arm64/lithium-arm64.h
diff --git a/src/arm64/lithium-arm64.h b/src/arm64/lithium-arm64.h
index 32c1161ee1842ac249b6c3cd568ba6ad94aae89f..21a5f741417790d1630108cb26b52afcfeacff6f 100644
--- a/src/arm64/lithium-arm64.h
+++ b/src/arm64/lithium-arm64.h
@@ -452,7 +452,7 @@ class LDrop V8_FINAL : public LTemplateInstruction<0, 0, 0> {
 
 class LDummy V8_FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
-  explicit LDummy() { }
+  LDummy() {}
   DECLARE_CONCRETE_INSTRUCTION(Dummy, "dummy")
 };
 
@@ -943,7 +943,7 @@ class LCheckInstanceType V8_FINAL : public LTemplateInstruction<0, 1, 1> {
 
 class LCheckMaps V8_FINAL : public LTemplateInstruction<0, 1, 1> {
  public:
-  LCheckMaps(LOperand* value = NULL, LOperand* temp = NULL) {
+  explicit LCheckMaps(LOperand* value = NULL, LOperand* temp = NULL) {
     inputs_[0] = value;
     temps_[0] = temp;
   }