Add tests for calls to nested, *non*-compile-time-resolveable functions
See https://github.com/thekid/php-src/commit/a1a4ba95117cca77b6a669d01b1cf97ea4fcb507#commitcomment-7414362
Fix nesting for *non*-compile-time-resolveable functions
See https://github.com/thekid/php-src/commit/a1a4ba95117cca77b6a669d01b1cf97ea4fcb507#commitcomment-7414223