Running individual tests from c-c++-common directory

[Peryt, Sebastian]

Hi,

I wanted to run individual test from gcc/testsuite/c-c++-common/ directory,
but unfortunately there is no *.exp file as it is in other directories. This prevents me from 
running it as for i386 e.g.: make check RUNTESTFLAGS="i386.exp=avx512*".

I also couldn't find anything related to those tests in documentation. Is there any special
approach for that?

Thanks,
Sebastian