Move print to corelib.

runtime/vm/benchmark_test.h

Index: runtime/vm/benchmark_test.h
diff --git a/runtime/vm/benchmark_test.h b/runtime/vm/benchmark_test.h
index 4b27abdf0d8e6fef1edb322abbacf3dd6101f7f6..ec357d2c0dd08e6b790d740f88dbecd91ebea20d 100644
--- a/runtime/vm/benchmark_test.h
+++ b/runtime/vm/benchmark_test.h
@@ -12,6 +12,7 @@
 #include "vm/heap.h"
 #include "vm/isolate.h"
 #include "vm/object.h"
+#include "vm/unit_test.h"
 #include "vm/zone.h"
 
 namespace dart {
@@ -93,6 +94,19 @@ class BenchmarkIsolateScope {
   explicit BenchmarkIsolateScope(Benchmark* benchmark) : benchmark_(benchmark) {
     benchmark_->CreateIsolate(NULL);
     Dart_EnterScope();  // Create a Dart API scope for unit benchmarks.
+
+    // Setup builtin library mock for 'print' in coreimpl.
+    const char* builtin_source =
+        "#library('dart:builtin');\n"
+        "void print(Object o) { }";
+    Dart_Handle coreimpl = Dart_LookupLibrary(Dart_NewString("dart:coreimpl"));
+    EXPECT_VALID(coreimpl);
+    Dart_Handle builtin = Dart_LoadLibrary(Dart_NewString("dart:builtin"),
+                                           Dart_NewString(builtin_source));
+    EXPECT_VALID(builtin);
+    Dart_Handle imported =
+        Dart_LibraryImportLibrary(coreimpl, builtin, Dart_NewString("builtin"));
+    EXPECT_VALID(imported);
   }
   ~BenchmarkIsolateScope() {
     Dart_ExitScope();  // Exit the Dart API scope created for unit tests.