To prevent rounding errors converting to and from f64 change
`Amount::MAX` to `MAX_MONEY` which is below the limit in f64 that has
issues.
Add checks to `from_str_in`, `checked_add` and `checked_mul` that the
result is below MAX, where previously a u64 overflow was relied on.
Change tests to account for new lower MAX that is within the range of
SignedAmount and does not overflow so easily
Remove overflow tests
`Amount::MAX` is now below `u64::MAX` and within the range of values for
`SignedAmount`. These tests therefore do not overflow.
In effective_value there is no error with `Amount::MAX` and the correct
value is returned.
In psbt the removed test is effectively the same as the previous test.
Modify `Amount` tests to work with new `MAX`
Tests need to be changed that checked values above the new `MAX` or
`Amount::MAX` was out of range for `SignedAmount` which it isn't anymore
6950c0a7b5