`sam deploy` for deduped build checks presence of identical build artifact many times

### Describe your idea/feature/enhancement

I `sam deploy`-ed 17 lambdas which shares `CodeUri` and `Runtime` (thus deduped build is enabled).
Got following output:

```
Uploading to my-stack-name/eb7b8e83[...snip...] 17287115 / 17287115 (100.00%)
File with same data already exists at my-stack-name/eb7b8e83[...snip...], skipping upload
[... another identical 15 lines ...]
```

This output implies `sam deploy` unnecessarily uploads identical artifact.

### Proposal

Ignore identical upload.
It takes few seconds for each skipped upload.
Ignoring identical upload can improve performance of `sam deploy`.

### Additional Details