[vm] Fix function resolution so that it stops when it finds target even if it can't add method extractor.

The fact that function resolution returned a target led to incorrect range merging for polymorphic instance call sites.

Fixes flutter/flutter#19696
Fixes #37348

Change-Id: If6c53dd322f9788df241baf7071b98906336d2e5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/108860
Commit-Queue: Alexander Aprelev <[email protected]>
Reviewed-by: Ryan Macnak <[email protected]>

Author: aam

runtime/vm/resolver.cc

@@ -119,13 +119,17 @@ RawFunction* Resolver::ResolveDynamicAnyArgs(Zone* zone,
     if (FLAG_lazy_dispatchers) {
       if (is_getter && function.IsNull()) {
         function = cls.LookupDynamicFunction(demangled);
-        if (!function.IsNull() && allow_add) {
-          // We were looking for the getter but found a method with the same
-          // name. Create a method extractor and return it.
-          // The extractor does not exist yet, so using GetMethodExtractor is
-          // not necessary here.
-          function = function.CreateMethodExtractor(function_name);
-          return function.raw();
+        if (!function.IsNull()) {
+          if (allow_add) {
+            // We were looking for the getter but found a method with the same
+            // name. Create a method extractor and return it.
+            // The extractor does not exist yet, so using GetMethodExtractor is
+            // not necessary here.
+            function = function.CreateMethodExtractor(function_name);
+            return function.raw();
+          } else {
+            return Function::null();
+          }
         }
       }
     }