Add boundary test case to StringToDouble

The max presentable double is HUGE_VAL=(2^53-1)*(2^971). And
(2^53)*(2^971) is considered overflow.

Added cases above and below (2^53-0.5)*(2^971). The value above is
overflow and the value below is not.

std::strtod on linux doesn't pass the above case (it returns inf correctly
but doesn't set errno=ERANGE).

BUG=593512

Review-Url: https://codereview.chromium.org/2415353002
Cr-Commit-Position: refs/heads/master@{#425496}
1 file changed