empty(), isset(), eval() and die() parse as an ordinary
function_call_expression, so the call pass resolved them by bare name.
A reserved word has been a legal method name since PHP 7, so a class
that declares empty() collected every empty($x) in the corpus:
EXTRACTED from its sibling methods, INFERRED from every other file
through the case-insensitive fold.
Drop the callee for these constructs in the PHP branch, before the
in-file lookup and before raw_calls, the same way _GO_PREDECLARED_FUNCS
handles Go builtins. $bag->empty() is a member call and still resolves.
(cherry picked from commit 94574eb239)
Huanyi Xie