[php-src] Issue #8349: `isset` (and `??` operator) must emit a notice if the inner expression is non-array

Issue: https://github.com/php/php-src/issues/8349 Comment Author: bwoebi @mvorisek Parenthesis are abstracted away upon AST construction, they have no deeper meaning except providing explicit operator grouping instead of the default precedence. Wrapping something in a parenthesis does not magically separate values. $a and ($a) are identical for everything the compiler is concerned with. (like ($a)[0] = 1; does a write to $a.)