ARM test suite fixes

These changes are necessary to make the test suite pass on ARM.
It's mostly reducing the required precision of math tests or changes the test values if they're not valid for real==double systems.

Note: This is part of a set of changes which are required to get test suite & unit tests passing on ARM GDC. All necessary changes for GDC are here for reference:
https://github.com/jpf91/GDC/commits/arm-old

Once these pull requests are merged upstream I'll merge them into GDC as well.