Restrict inlining of matmul to those cases where assignment to the
result array does not need special treatment.
gcc/fortran/ChangeLog:
PR fortran/99839
* frontend-passes.c (inline_matmul_assign): Do not inline matmul
if the assignment to the resulting array if it is not of canonical
type (real/integer/complex/logical).
gcc/testsuite/ChangeLog:
PR fortran/99839
* gfortran.dg/inline_matmul_25.f90: New test.