Cleanup throwing of the RangeError in the runtime to remove duplicated code.

runtime/lib/string.cc

Index: runtime/lib/string.cc
diff --git a/runtime/lib/string.cc b/runtime/lib/string.cc
index 19222eb8c1d9db2bc6cc71d0c13fd35806462aa8..ce7731fde28884313fde54104e3508dfedca00fc 100644
--- a/runtime/lib/string.cc
+++ b/runtime/lib/string.cc
@@ -237,16 +237,12 @@ static int32_t StringValueAt(const String& str, const Integer& index) {
     const Smi& smi = Smi::Cast(index);
     intptr_t index = smi.Value();
     if ((index < 0) || (index >= str.Length())) {
-      const Array& args = Array::Handle(Array::New(1));
-      args.SetAt(0, smi);
-      Exceptions::ThrowByType(Exceptions::kRange, args);
+      Exceptions::ThrowRangeError(smi);
     }
     return str.CharAt(index);
   } else {
     // An index larger than Smi is always illegal.
-    const Array& args = Array::Handle(Array::New(1));
-    args.SetAt(0, index);
-    Exceptions::ThrowByType(Exceptions::kRange, args);
+    Exceptions::ThrowRangeError(index);
     return 0;
   }
 }
@@ -336,9 +332,7 @@ DEFINE_NATIVE_ENTRY(StringBuffer_createStringFromUint16Array, 3) {
   intptr_t array_length = codeUnits.Length();
   intptr_t length_value = length.Value();
   if (length_value < 0 || length_value > array_length) {
-    const Array& args = Array::Handle(Array::New(1));
-    args.SetAt(0, length);
-    Exceptions::ThrowByType(Exceptions::kRange, args);
+    Exceptions::ThrowRangeError(length);
   }
   const String& result = isLatin1.value()
       ? String::Handle(OneByteString::New(length_value, Heap::kNew))