Fix Number.prototype.toString with non-default radix wrt modulo.

test/mjsunit/number-tostring.js

Index: test/mjsunit/number-tostring.js
diff --git a/test/mjsunit/number-tostring.js b/test/mjsunit/number-tostring.js
index d428b697fe88639c3ad5a4a6baad4ffa55a14ecd..83aa3ed2dabaa429c6d494952ac824e8d884cbe9 100644
--- a/test/mjsunit/number-tostring.js
+++ b/test/mjsunit/number-tostring.js
@@ -151,6 +151,9 @@ assertEquals("10000", (81).toString(3));
 assertEquals("10000.01", (81 + 1/9).toString(3));
 assertEquals("0.0212010212010212010212010212010212", (2/7).toString(3));
 
+assertEquals("314404114120101444444424000000000000000",
+             (1.2345e+27).toString(5));
+
 // ----------------------------------------------------------------------
 // toFixed
 assertEquals("NaN", (NaN).toFixed(2));