Fixed typos: defintion to definition.

runtime/vm/intermediate_language.cc

Index: runtime/vm/intermediate_language.cc
diff --git a/runtime/vm/intermediate_language.cc b/runtime/vm/intermediate_language.cc
index 93c2e1ec03472da606c84aee3f2e7bd835ccdc66..ef8e9a3325f98033876d880a6cb2acc0f93ce5e3 100644
--- a/runtime/vm/intermediate_language.cc
+++ b/runtime/vm/intermediate_language.cc
@@ -1498,7 +1498,7 @@ void PushArgumentInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
 }
 
 
-// Helper to either use the constant value of a defintion or the defintion.
+// Helper to either use the constant value of a definition or the definition.
 static Value* UseDefinition(Definition* defn) {
   if (defn->IsBind() && defn->AsBind()->computation()->IsConstant()) {
     return defn->AsBind()->computation()->AsConstant();