Avoid array bounds check when allowed by guarded field.

runtime/vm/intermediate_language.h

Index: runtime/vm/intermediate_language.h
diff --git a/runtime/vm/intermediate_language.h b/runtime/vm/intermediate_language.h
index 644cb99c8471c14976986bf7cbdfda90c3ed077d..38ee18dd00fd15d008fe5eb5af20865e76778f19 100644
--- a/runtime/vm/intermediate_language.h
+++ b/runtime/vm/intermediate_language.h
@@ -6488,7 +6488,8 @@ class CheckSmiInstr : public TemplateInstruction<1> {
 
 class CheckArrayBoundInstr : public TemplateInstruction<2> {
  public:
-  CheckArrayBoundInstr(Value* length, Value* index, intptr_t deopt_id) {
+  CheckArrayBoundInstr(const Field* array, Value* length, Value* index,
+                       intptr_t deopt_id) : array_(array) {
     SetInputAt(kLengthPos, length);
     SetInputAt(kIndexPos, index);
     // Override generated deopt-id.
@@ -6527,6 +6528,8 @@ class CheckArrayBoundInstr : public TemplateInstruction<2> {
     kIndexPos = 1
   };
 
+  const Field* array_;
+
   DISALLOW_COPY_AND_ASSIGN(CheckArrayBoundInstr);
 };