[Code scan] Make clean_build.sh succeed when no shared libraries exist

This issue comes from a Codex global scan of deepmodeling/tbplas at commit 4d3652b3dba8eb930e4869a6d41074f62d703692.

Severity: Low

`clean_build.sh` pipes `find . -name "*.so"` into `xargs rm`. On a clean tree with no shared libraries, `xargs` still runs `rm` with no operands, causing the script to exit nonzero.

Code reference:
https://github.com/deepmodeling/tbplas/blob/4d3652b3dba8eb930e4869a6d41074f62d703692/scripts/clean_build.sh#L1-L5

Suggested fix: use `find . -name "*.so" -delete`, or `xargs -r rm` where GNU xargs is available.

Start with scripts/clean_build.sh at lines 1–5 and reproduce the command on a clean tree with no .so files. Make the cleanup succeed without passing empty input to rm, then run the script on both clean and build-containing trees to confirm shared libraries are removed and the command exits successfully.

Written by the indexing model from the issue text.