Polish dy2st error message (#52527)

python/paddle/jit/dy2static/error.py

@@ -245,12 +245,18 @@ class ErrorData:
 
         # Simplify error value to improve readability if error is raised in runtime
         if self.in_runtime:
-            if int(
-                os.getenv(SIMPLIFY_ERROR_ENV_NAME, DEFAULT_SIMPLIFY_NEW_ERROR)
-            ):
-                self._simplify_error_value()
-            message_lines.append(str(self.error_value))
-            return '\n'.join(message_lines)
+            try:
+                if int(
+                    os.getenv(
+                        SIMPLIFY_ERROR_ENV_NAME, DEFAULT_SIMPLIFY_NEW_ERROR
+                    )
+                ):
+                    self._simplify_error_value()
+            except:
+                pass
+            else:
+                message_lines.append(str(self.error_value))
+                return '\n'.join(message_lines)
 
         # Step2: Optimizes stack information with source code information of dygraph from user.
         user_code_traceback_index = []