string representation of floats larger than 2^53 differs from other engines

[sunlili]

Hello,
The following code behaves incorrectly (inconsistent with the standard and other engines).
ch version 1.8.5.0

var nonArray=({                                                                                                                                                      
    length:4,
    0:42,
    2:37,
    0xf7da5000:undefined,
    0x8000000000000800:0
});
Array.prototype.sort.call(nonArray);

print(JSON.stringify(nonArray));
print("BT_FLAG");

The output is:
{"0":37,"1":42,"length":4,"9223372036854777000":0}
BT_FLAG

However, other engines' output are:
{"0":37,"1":42,"length":4,"9223372036854778000":0}
BT_FLAG

BT group
2018.6.25

[zenparsing]

Minimum repro:

print(0x8000000000000800);

[rhuanjl]

Possibly a duplicate of this issue #149