Fix phpGH-15923: GDB: Python Exception <class 'TypeError'>: exceptions must derive from BaseException

Triggers on release builds when printing data structures.
You can't raise a string, you must raise exceptions.

Author: nielsdos

scripts/gdb/php_gdb.py

@@ -301,7 +301,7 @@ def load_type_bits():
 
     (symbol,_) = gdb.lookup_symbol("zend_gc_refcount")
     if symbol == None:
-        raise "Could not find zend_types.h: symbol zend_gc_refcount not found"
+        raise Exception("Could not find zend_types.h: symbol zend_gc_refcount not found")
     filename = symbol.symtab.fullname()
 
     bits = {}