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/utils/arm/assembler_arm_test.h b/compiler/utils/arm/assembler_arm_test.h
index a85a05e..8c3a11f2 100644
--- a/compiler/utils/arm/assembler_arm_test.h
+++ b/compiler/utils/arm/assembler_arm_test.h
@@ -512,7 +512,7 @@
   }
 
  protected:
-  explicit AssemblerArmTest() {}
+  AssemblerArmTest() {}
 
   virtual std::vector<Cond>& GetConditions() = 0;
   virtual std::string GetConditionString(Cond c) = 0;
diff --git a/compiler/utils/assembler_test.h b/compiler/utils/assembler_test.h
index ad84412..0cb8bbb 100644
--- a/compiler/utils/assembler_test.h
+++ b/compiler/utils/assembler_test.h
@@ -734,7 +734,7 @@
   }
 
  protected:
-  explicit AssemblerTest() {}
+  AssemblerTest() {}
 
   void SetUp() OVERRIDE {
     allocator_.reset(new ArenaAllocator(&pool_));
diff --git a/compiler/utils/assembler_test_base.h b/compiler/utils/assembler_test_base.h
index 2ef43bd..1482210 100644
--- a/compiler/utils/assembler_test_base.h
+++ b/compiler/utils/assembler_test_base.h
@@ -37,7 +37,7 @@
 
 // Use a glocal static variable to keep the same name for all test data. Else we'll just spam the
 // temp directory.
-static std::string tmpnam_;
+static std::string tmpnam_;  // NOLINT [runtime/string] [4]
 
 // We put this into a class as gtests are self-contained, so this helper needs to be in an h-file.
 class AssemblerTestInfrastructure {
diff --git a/compiler/utils/atomic_dex_ref_map.h b/compiler/utils/atomic_dex_ref_map.h
index fad056c..205543f 100644
--- a/compiler/utils/atomic_dex_ref_map.h
+++ b/compiler/utils/atomic_dex_ref_map.h
@@ -29,7 +29,7 @@
 template <typename DexFileReferenceType, typename Value>
 class AtomicDexRefMap {
  public:
-  explicit AtomicDexRefMap() {}
+  AtomicDexRefMap() {}
   ~AtomicDexRefMap() {}
 
   // Atomically swap the element in if the existing value matches expected.
diff --git a/compiler/utils/jni_macro_assembler_test.h b/compiler/utils/jni_macro_assembler_test.h
index 34ab4c3..1aefc84 100644
--- a/compiler/utils/jni_macro_assembler_test.h
+++ b/compiler/utils/jni_macro_assembler_test.h
@@ -55,7 +55,7 @@
   }
 
  protected:
-  explicit JNIMacroAssemblerTest() {}
+  JNIMacroAssemblerTest() {}
 
   void SetUp() OVERRIDE {
     allocator_.reset(new ArenaAllocator(&pool_));
diff --git a/compiler/utils/label.h b/compiler/utils/label.h
index d835c63..b9d4e9c 100644
--- a/compiler/utils/label.h
+++ b/compiler/utils/label.h
@@ -27,23 +27,23 @@
 class AssemblerFixup;
 
 namespace arm64 {
-  class Arm64Assembler;
+class Arm64Assembler;
 }  // namespace arm64
 namespace mips {
-  class MipsAssembler;
-  class MipsLabel;
+class MipsAssembler;
+class MipsLabel;
 }  // namespace mips
 namespace mips64 {
-  class Mips64Assembler;
-  class Mips64Label;
+class Mips64Assembler;
+class Mips64Label;
 }  // namespace mips64
 namespace x86 {
-  class X86Assembler;
-  class NearLabel;
+class X86Assembler;
+class NearLabel;
 }  // namespace x86
 namespace x86_64 {
-  class X86_64Assembler;
-  class NearLabel;
+class X86_64Assembler;
+class NearLabel;
 }  // namespace x86_64
 
 class ExternalLabel {