[GR-26640] Remove slow-path method

Author: timfel

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/PythonBuiltinClassType.java

@@ -281,11 +281,6 @@ public final Shape getInstanceShape(PythonLanguage lang) {
         return lang.getBuiltinTypeInstanceShape(this);
     }
 
-    public final Shape getInstanceShape() {
-        CompilerDirectives.bailout("slow path operation");
-        return PythonLanguage.getCurrent().getBuiltinTypeInstanceShape(this);
-    }
-
     @CompilationFinal(dimensions = 1) public static final PythonBuiltinClassType[] VALUES = Arrays.copyOf(values(), values().length - 1);
     @CompilationFinal(dimensions = 1) public static final PythonBuiltinClassType[] EXCEPTIONS;