Address more review comments on commit
2d819a08a1.
Based on comments from Peter Eisentraut.
* Document CREATE DATABASE ... BUILTIN_LOCALE.
* Determine required encoding based on locale name for CREATE
COLLATION. Use -1 for "C" (requires catversion bump).
* initdb output fixups.
* Make ctype_is_c a constant true for now.
* Fixups to ICU 010_create_database.pl test.
Discussion: https://postgr.es/m/
4135cf11-206d-40ed-96c0-
9363c1232379@eisentraut.org