Use array_length instead of "sizeof arr / sizeof (TYPE)".

One increment in the process of converting manual array-length computations to the array_length macro. This change converts about 200 instances in a small number of files. Another (approx.) 170 instances remain, scattered throughout a larger number of separate files.

Comparison of the built object files before and after this commit confirms that the only net effect of this change is in the .debug_line section, so this commit will not actually change any program behavior. This also helps assure that all the removed "(TYPE)" expressions did indeed correctly reflect the array type.