std::ios_base::floatfield misused in jsontest.h

[BillyDonahue]

TestResult operator<< uses

oss.setf(std::ios_base::floatfield);

This is inappropriate. The ios_base::floatfield is a mask, not a value.
This essentially selects hexfloat output, but if we wanted to do that we should do it explicitly.

Reproduce

This essentially what our TestResult operator is doing:

https://gcc.godbolt.org/z/e93L45

#include <iostream>
int main() {
    std::cout.setf(std::ios_base::floatfield);
    std::cout << "f:" << 3.14 << std::endl;
}
Output:
f:0x1.91eb851eb851fp+1

Expected behavior
I think we didn't want hexfloat output, or we would have asked for it by name.
I'm guessing the intent was to clear the floatfield, and we do that with unsetf.

None of our unit tests actually call operator<< with a floating point value, so it never mattered. We should fix the bug anyway.

[cdunn2001]

floatfield came from:

commit f587e6a420c467a69b7f977875052077aef2913b
Author: Baptiste Lepilleur <baptiste.lepilleur@gmail.com>
Date:   Thu May 26 15:55:24 2011

    Fixed compilation issues with MSVC 6: replace usage of ostringstream with valueToString to support 64 bits integer and high precision floating point conversion to string.

I guess nobody else ever thought to check it! I merged your PR. You can close this, or leave it open to try << with a float.

[BillyDonahue]

fixed by 638ad26