Adding missing break from case statement.

src/ia32/stub-cache-ia32.cc

Index: src/ia32/stub-cache-ia32.cc
===================================================================
--- src/ia32/stub-cache-ia32.cc	(revision 7356)
+++ src/ia32/stub-cache-ia32.cc	(working copy)
@@ -3606,6 +3606,7 @@
                 __ bind(&done);
               }
               __ mov_b(Operand(edi, ebx, times_1, 0), ecx);
+              break;
             case kExternalByteArray:
             case kExternalUnsignedByteArray:
               __ mov_b(Operand(edi, ebx, times_1, 0), ecx);