To avoid duplicate type checks. In debug builds arginfo is still
checked and will generate an assertions if the function doesn't
subsequently throw an exception.
Some test results change due to differences in zpp and arginfo
error messages.
PHP requires boolean typehints to be written "bool" and disallows
"boolean" as an alias. This changes the error messages to match
the actual type name and avoids confusing messages like "must be
of type boolean, boolean given".
This a followup to ce1d69a1f6, which
implements the same change for integer->int.
