Fix a bunch of spelling mistakes :\

src/macro-assembler-arm.cc

Index: src/macro-assembler-arm.cc
diff --git a/src/macro-assembler-arm.cc b/src/macro-assembler-arm.cc
index 5cbeae9124c3a01c5aa2e16366b1c505cb7a6cc0..dc6d40fe362ea8d6b8368aad1ddec0295942439e 100644
--- a/src/macro-assembler-arm.cc
+++ b/src/macro-assembler-arm.cc
@@ -913,7 +913,7 @@ void MacroAssembler::Abort(const char* msg) {
   // We want to pass the msg string like a smi to avoid GC
   // problems, however msg is not guaranteed to be aligned
   // properly. Instead, we pass an aligned pointer that is
-  // a proper v8 smi, but also pass the aligment difference
+  // a proper v8 smi, but also pass the alignment difference
   // from the real pointer as a smi.
   intptr_t p1 = reinterpret_cast<intptr_t>(msg);
   intptr_t p0 = (p1 & ~kSmiTagMask) + kSmiTag;