Cleanup include guards:

src/arm/constants-arm.h

Index: src/arm/constants-arm.h
diff --git a/src/arm/constants-arm.h b/src/arm/constants-arm.h
index 919a8929ba302ce7adb99c565d56dca07a95b57b..66c6a8d8647fecbb48ffa36db9a38ef4384af78f 100644
--- a/src/arm/constants-arm.h
+++ b/src/arm/constants-arm.h
@@ -25,8 +25,8 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-#ifndef V8_CONSTANTS_ARM_H_
-#define V8_CONSTANTS_ARM_H_
+#ifndef V8_ARM_CONSTANTS_ARM_H_
+#define V8_ARM_CONSTANTS_ARM_H_
 
 namespace assembler { namespace arm {
 
@@ -237,4 +237,4 @@ class Instr {
 
 } }  // namespace assembler::arm
 
-#endif  // V8_CONSTANTS_ARM_H_
+#endif  // V8_ARM_CONSTANTS_ARM_H_