We need to check BigInt::to_f64() for infinity explicitly.

[ltratt]

Other SOMs that I've tried error (whether deliberately or not) when a big integer is too big to be represented as a floating point number. The BigInt::to_f64() function used to return None in such cases but now they always return Some::(f64::INFINITY) (see https://github.com/rust-num/num-bigint/pull/163). This PR handles that explicitly.

On the plus side, we can simplify our code a little bit; on the downside we'll also probably be a tiny bit slower in the common case.

[ltratt]

bors try

[bors[bot]]

try

Build succeeded:

• buildbot/buildbot-build-script

[ptersilie]

Please squash.

[ltratt]

Squashed.

[ptersilie]

bors r+

[bors[bot]]

Timed out.

[ltratt]

@ptersilie I think we need to retry bors.

[ptersilie]

bors r+

[bors[bot]]

Build succeeded:

• buildbot/buildbot-build-script