Summary:
## Description
Related issue: https://github.com/facebookresearch/faiss/issues/3246
When reading HNSWPQ from disk, if index ~read only~ new `IO_FLAG_PQ_SKIP_SDC_TABLE` flag is set, skip initializing the sdc_table.
In addition, adds cpp test case verifying functionality and build test util header file to share creation of temporary files amongst tests.
Pull Request resolved: https://github.com/facebookresearch/faiss/pull/3250
Test Plan: buck test //faiss/tests/:test_disable_pq_sdc_tables
Reviewed By: junjieqi
Differential Revision: D53844075
Pulled By: mdouze
fbshipit-source-id: e9a83c0e5243867edbca8f80e3b1242b38ef6a42
John Mazanec