Infer guaranteed types for static calls that are only called once.

dart/tests/compiler/dart2js/compiler_helper.dart

Index: dart/tests/compiler/dart2js/compiler_helper.dart
diff --git a/dart/tests/compiler/dart2js/compiler_helper.dart b/dart/tests/compiler/dart2js/compiler_helper.dart
index bf2fa672b65e62ac7e8c6274a9dcfa774f4ea3da..d4da4854e06232c071f809fc57f3656ed76b683d 100644
--- a/dart/tests/compiler/dart2js/compiler_helper.dart
+++ b/dart/tests/compiler/dart2js/compiler_helper.dart
@@ -24,10 +24,15 @@ String compile(String code, [String entry = 'main']) {
   return generated;
 }
 
-String compileAll(String code) {
+MockCompiler compilerFor(String code, Uri uri) {
   MockCompiler compiler = new MockCompiler();
-  Uri uri = new Uri.fromComponents(scheme: 'source');
   compiler.sourceFiles[uri.toString()] = new SourceFile(uri.toString(), code);
+  return compiler;
+}
+
+String compileAll(String code) {
+  Uri uri = new Uri.fromComponents(scheme: 'source');
+  MockCompiler compiler = compilerFor(code, uri);
   compiler.runCompiler(uri);
   return compiler.assembledCode;
 }