[SPARK-15112][SQL] Disables EmbedSerializerInFilter for plan fragments that change schema

## What changes were proposed in this pull request?

`EmbedSerializerInFilter` implicitly assumes that the plan fragment being optimized doesn't change plan schema, which is reasonable because `Dataset.filter` should never change the schema.

However, due to another issue involving `DeserializeToObject` and `SerializeFromObject`, typed filter *does* change plan schema (see [SPARK-15632][1]). This breaks `EmbedSerializerInFilter` and causes corrupted data.

This PR disables `EmbedSerializerInFilter` when there's a schema change to avoid data corruption. The schema change issue should be addressed in follow-up PRs.

## How was this patch tested?

New test case added in `DatasetSuite`.

[1]: https://issues.apache.org/jira/browse/SPARK-15632

Author: Cheng Lian <lian@databricks.com>

Closes #13362 from liancheng/spark-15112-corrupted-filter.