Fix spelling mistake

lib/compiler/implementation/ssa/optimize.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 interface OptimizationPhase {
   String get name();
   void visitGraph(HGraph graph);
 }
 
 class SsaOptimizerTask extends CompilerTask {
@@ skipping 1225 matching lines @@
           case Compiler.PHASE_COMPILING:
             compiler.enqueuer.codegen.registerRecompilationCandidate(
                 work.element);
             break;
           case Compiler.PHASE_RECOMPILING:
             if (compiler.codegenWorld.hasInvokedSetter(field.element,
                                                        compiler)) {
               // If there are invoked setters we don't know for sure that the
               // field will hold the calculated, but the fact that the class
               // itself stick to this type in the field is still a strong
-              // signal to indiate the expected type of the field.
+              // signal to indicate the expected type of the field.
               field.propagatedType = type;
               graph.highTypeLikelyhood = true;
             } else {
               // If there are no invoked setters we know the type of this
               // field for sure.
               field.guaranteedType = type;
             }
             break;
           default:
             assert(false);
@@ skipping 51 matching lines @@
             }
             break;
           default:
             assert(false);
             break;
         }
       }
     }
   }
 }