Disable GVN for interceptors and fields.

lib/compiler/implementation/ssa/nodes.dart

Index: lib/compiler/implementation/ssa/nodes.dart
diff --git a/lib/compiler/implementation/ssa/nodes.dart b/lib/compiler/implementation/ssa/nodes.dart
index 68a91ff249edf311d06b64a909c52eb718ef0981..19b4977b72800fdd696e395fdbf5508f13c7d447 100644
--- a/lib/compiler/implementation/ssa/nodes.dart
+++ b/lib/compiler/implementation/ssa/nodes.dart
@@ -1271,9 +1271,7 @@ class HInvokeInterceptor extends HInvokeStatic {
 
   void prepareGvn() {
     if (isLengthGetterOnStringOrArray()) {
-      setUseGvn();
       clearAllSideEffects();
-      setDependsOnSomething();
     } else {
       setAllSideEffects();
     }
@@ -1304,8 +1302,7 @@ class HFieldGet extends HFieldAccess {
   accept(HVisitor visitor) => visitor.visitFieldGet(this);
 
   void prepareGvn() {
-    setUseGvn();
-    if (!isFinalOrConst) setDependsOnSomething();
+    clearAllSideEffects();
   }
 
   int typeCode() => 27;