tonumber produces wrong results for large exponents

[XmiliaH]

Large exponents in numbers are cut of by

LuaJIT/src/lj_strscan.c

Line 464 in a91d0d9

if (xx < 65536) xx = xx * 10 + (*p & 15);

without handling the cut. This can result in wrong numbers as is the case in

print(tonumber("0." .. string.rep("0", 99999) .. "1e100000"))
print(tonumber("0." .. string.rep("0", 999999) .. "1e1000000"))

where the second number should be 1 but is calculated as 0.

[MikePall]

Fixed. Thanks!