Avoid generic verify scan when no turbofish args

[prateekbhujel]

zend_try_inline_call() only needs to scan back for VERIFY_GENERIC_ARGUMENTS when the current op array actually has turbofish args recorded.

For non-generic call sites, op_array->generic_types or op_array->generic_types->turbofish_args is empty, so the scan cannot find anything useful.

Tests run:

sapi/cli/php run-tests.php -q \
  Zend/tests/generics/syntax/turbofish_function_call.phpt \
  Zend/tests/generics/syntax/turbofish_method_call.phpt \
  Zend/tests/generics/syntax/turbofish_new.phpt \
  Zend/tests/generics/turbofish/arity/function_too_many.phpt \
  Zend/tests/generics/turbofish/arity/non_generic_callee.phpt \
  Zend/tests/generics/turbofish/bounds/function_call_violates.phpt \
  Zend/tests/generics/erasure/turbofish_no_runtime_effect.phpt \
  Zend/tests/generics/turbofish/bounds/attribute_under_opcache.phpt \
  ext/opcache/tests/optimize_func_calls.phpt \
  ext/opcache/tests/wrong_inlining_001.phpt \
  ext/opcache/tests/bug77691.phpt

sapi/cli/php run-tests.php -q Zend/tests/generics ext/reflection/tests/generics

Result: 407/407 passed for the full generics + reflection generics suite.