Large integers print as hex

[DartBot]

This issue was originally filed by rice@google.com

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main() {
  print("9223372036854775807 = ${9223372036854775807}"); // 0x7fffffffffffffff = 2^63 - 1
  print("9223372036854775808 = ${9223372036854775808}"); // 0x8000000000000000 = 2^63
}

prints:

9223372036854775807 = 9223372036854775807
9223372036854775808 = 0x8000000000000000

I would not expect to see hex output unless I specifically requested it.

[ghost]

This is a DartVM issue. The integer overflows into a BigInt which can currently be printed only in hex format.

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Set owner to @sgmitrovic.
Removed Area-Library label.
Added Area-VM, Accepted labels.

[ghost]

Fixed in r1058. Please note that used BN_bn2dec is very inefficient.

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Added Fixed label.