ART: Add missing namespace comments

Add closing namespace comments.

Bug: 32619234
Test: m
Change-Id: I1f50e09dcd1038c4b540b87e5c19e319c1f592e4
diff --git a/compiler/utils/label.h b/compiler/utils/label.h
index 0f82ad5..4c6ae8e 100644
--- a/compiler/utils/label.h
+++ b/compiler/utils/label.h
@@ -29,24 +29,24 @@
 namespace arm {
   class ArmAssembler;
   class Thumb2Assembler;
-}
+}  // namespace arm
 namespace arm64 {
   class Arm64Assembler;
-}
+}  // namespace arm64
 namespace mips {
   class MipsAssembler;
-}
+}  // namespace mips
 namespace mips64 {
   class Mips64Assembler;
-}
+}  // namespace mips64
 namespace x86 {
   class X86Assembler;
   class NearLabel;
-}
+}  // namespace x86
 namespace x86_64 {
   class X86_64Assembler;
   class NearLabel;
-}
+}  // namespace x86_64
 
 class ExternalLabel {
  public:
diff --git a/compiler/utils/managed_register.h b/compiler/utils/managed_register.h
index 184cdf5..2b7b2aa 100644
--- a/compiler/utils/managed_register.h
+++ b/compiler/utils/managed_register.h
@@ -26,24 +26,24 @@
 
 namespace arm {
 class ArmManagedRegister;
-}
+}  // namespace arm
 namespace arm64 {
 class Arm64ManagedRegister;
-}
+}  // namespace arm64
 namespace mips {
 class MipsManagedRegister;
-}
+}  // namespace mips
 namespace mips64 {
 class Mips64ManagedRegister;
-}
+}  // namespace mips64
 
 namespace x86 {
 class X86ManagedRegister;
-}
+}  // namespace x86
 
 namespace x86_64 {
 class X86_64ManagedRegister;
-}
+}  // namespace x86_64
 
 class ManagedRegister : public ValueObject {
  public: