Get ClassLinker out of the business of allocating strings.

String is now the only place we allocate strings. This requires
a bit of finesse in order to make char[] available early during
bootstrap.

Change-Id: I494a2b0691b58fdafc96513c1e697a88d437c805
diff --git a/src/object_test.cc b/src/object_test.cc
index 46e9cca..d240d0c 100644
--- a/src/object_test.cc
+++ b/src/object_test.cc
@@ -27,7 +27,7 @@
       utf16_expected[i] = ch;
     }
 
-    String* string = class_linker_->AllocStringFromModifiedUtf8(length, utf8_in);
+    String* string = String::AllocFromModifiedUtf8(length, utf8_in);
     ASSERT_EQ(length,  static_cast<size_t>(string->count_));
     ASSERT_TRUE(string->array_ != NULL);
     ASSERT_TRUE(string->array_->GetChars() != NULL);