wrong estimaton when there're optimizable predicates and prepared plan cache is enabled.

## Bug Report

Please answer these questions before submitting your issue. Thanks!

### 1. Minimal reproduce step (Required)

The desensitized example is not ready yet.

We perform a prepared statement.
Then we will see the row count estimation is different for `col_a in (..) and col_a = ..` and `col_a = ..`.

### 2. What did you expect to see? (Required)

### 3. What did you see instead (Required)

### 4. What is your TiDB version? (Required)

master