[Patch, Fortran] PR 44352: Fix String-assigning ICE with statement functions

[Dominique Dhumieres]

Tobias,

The patch fixes the ICEs I get with the different avatars in pr44352.
It passed my tests and the testsuite. However the test in comment#8
of the pr with the following change

-      dname(c) =   'h810 e=0.01         '//c
+      dname(c) =   'h810 e=0.01         '

gives the following error

[macbook] f90/bug% gfc pr44352_2_db.f90
pr44352_2_db.f90:5.19:

      ddname=dname("w")
                   1
Warning: Character length of actual argument shorter than of dummy argument 'c' (1/4) at (1)
pr44352_2_db.f90: In function 'MAIN__':
pr44352_2_db.f90:5:0: error: size of variable 'c.0' is too large

Thanks for the patch,

Dominique