Fortran: check types of source expressions before conversion [PR107215]

gcc/fortran/ChangeLog:

	PR fortran/107215
	* arith.cc (gfc_int2int): Check validity of type of source expr.
	(gfc_int2real): Likewise.
	(gfc_int2complex): Likewise.
	(gfc_real2int): Likewise.
	(gfc_real2real): Likewise.
	(gfc_complex2int): Likewise.
	(gfc_complex2real): Likewise.
	(gfc_complex2complex): Likewise.
	(gfc_log2log): Likewise.
	(gfc_log2int): Likewise.
	(gfc_int2log): Likewise.

gcc/testsuite/ChangeLog:

	PR fortran/107215
	* gfortran.dg/pr107215.f90: New test.