Suppress noreturn attribute suggestion
Suppress noreturn attribute suggestion

Marking `CTEST_ERR` function as noreturn leads to same warning appearing
for `ctest_fail` function; marking the latter as noreturn as well leads
to warnings in user test cases which is not something we want.

This eliminates "function 'CTEST_ERR' could be declared with attribute
'noreturn' [-Wmissing-noreturn]" Clang warning.

bvdberg/ctest