Added failing test case for bug found in mpir.h header.
Added failing test case for bug found in mpir.h header.

jpflori/flint2,wbhart/flint2,dsroche/flint2,dsroche/flint2,jpflori/flint2,wbhart/flint2,fredrik-johansson/flint2,jpflori/flint2,fredrik-johansson/flint2,dsroche/flint2,wbhart/flint2,dsroche/flint2,fredrik-johansson/flint2,jpflori/flint2