Revert "fix test runner"

This reverts commit 8c42dd1f6735eddea1d7441f31bb5839441e794d.
Revert "Support named unittests"

This reverts commit 9bc336d703c4dcfbc087eeb901e447dbba2f72bb.
Revert "Use new unittest format in default runner"

This reverts commit 64aa857d3e3c771b935064ad6d6575c4c40cfe42.
Revert "Add enhanced unittest runtime information"

This reverts commit 9279278770dd3523d759585bea5283cd69be5cf7.
Fix build on PPC64.

Add the missing `fenv_t` and `fexcept_t` types.
Rename DigitalMarsWin32 / DigitalMarsWin64 to DMC_RUNTIME / MSVC_RUNTIME.

This has the advantages:
- DMC_RUNTIME is used in Phobos, too.
- I don't have to write

    version(LDC) version(Win64) version = DigitalMarsWin64;

which I find confusing.
Merge pull request #852 from redstar/ppc64fenv

Fix build on PPC64.
Merge pull request #832 from jpf91/revertUnittest

Revert new unittest changes in druntime
Merge pull request #853 from redstar/msvcrt

Rename DigitalMarsWin32 / DigitalMarsWin64 to DMC_RUNTIME / MSVC_RUNTIME