* ext/oci8: use zend_string_equals()
Eliminate duplicate code.
* main/php_variables: use zend_string_equals_literal()
Eliminate duplicate code.
* Zend/zend_string: add zend_string_equals_cstr()
Allows eliminating duplicate code.
* Zend, ext/{opcache,standard}, main/output: use zend_string_equals_cstr()
Eliminate duplicate code.
* Zend/zend_string: add zend_string_starts_with()
* ext/{opcache,phar,spl,standard}: use zend_string_starts_with()
This adds missing length checks to several callers, e.g. in
cache_script_in_shared_memory(). This is important when the
zend_string is shorter than the string parameter, when memcmp()
happens to check backwards; this can result in an out-of-bounds memory
access.