Compress deopt instructions in memory using variable length encoding.

runtime/vm/growable_array.h

Index: runtime/vm/growable_array.h
diff --git a/runtime/vm/growable_array.h b/runtime/vm/growable_array.h
index 81a946bb33ac34379acafa6696ce8c85bfc12a2f..ba6f80756bea9ba1b45b2423d0bfaf08cfaa413d 100644
--- a/runtime/vm/growable_array.h
+++ b/runtime/vm/growable_array.h
@@ -90,6 +90,15 @@ class BaseGrowableArray : public B {
     data_[idx] = value;
   }
 
+  void Reverse() {
+    for (intptr_t i = 0; i < length_ / 2; i++) {
+      const intptr_t j = length_ - 1 - i;
+      T temp = data_[i];
+      data_[i] = data_[j];
+      data_[j] = temp;
+    }
+  }
+
   // The content is uninitialized after calling it.
   void SetLength(intptr_t new_length);