Use ASCII case conversion instead of locale-dependent case conversion in
the following places:
* grapheme_stripos() and grapheme_strripos() in the "fast" path
* ldap_get_entries()
* oci_pconnect() for case folding of parameters when constructing a key
into the connection or session pool
* SoapClient: case folding of function names
* get_meta_tags(): case conversion of property names
* http stream wrapper: header names
* phpinfo(): anchor names
* php_verror(): docref URLs
* rfc1867.c: Content-Type boundary parameter name
* streams.c: stream protocol names
Using locale-dependent case folding for these cases is either
unnecessary or actively incorrect. These functions could have
misbehaved when used with certain locales (e.g. Turkish).
Closes GH-7511.
c96be7b8f2