Finish implementing lazy deoptimization (ia32, x64). Ran tests with --deoptimize-alot.

runtime/vm/instructions_x64.cc

Index: runtime/vm/instructions_x64.cc
===================================================================
--- runtime/vm/instructions_x64.cc	(revision 12015)
+++ runtime/vm/instructions_x64.cc	(working copy)
@@ -53,6 +53,17 @@
 }
 
 
+void ShortCallPattern::SetTargetAddress(uword target) const {
+  ASSERT(IsValid());
+  *reinterpret_cast<uint32_t*>(start() + 1) = target - start() - kLengthInBytes;
+}
+
+
+const int* ShortCallPattern::pattern() const {
+  static const int kCallPattern[kLengthInBytes] = {0xE8, -1, -1, -1, -1};
+  return kCallPattern;
+}
+
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64