fix ARM64 SVE CI due to openblas version bump (#3777)

Summary:
Pull Request resolved: #3777

openblas version is bumped from 0.3.27 -> 0.3.28 in the last 3 days. This caused the below test to fail. Confirmed with algoriddle bumping nprobe is okay to do

Reviewed By: algoriddle

Differential Revision: D61536541

fbshipit-source-id: 1e83f75011517ba7b856520f11526e72a00494a5

Author: mengdilin

tests/test_index_accuracy.py

@@ -633,14 +633,14 @@ def test_OIVFPQ(self):
         d = ev.d
         quantizer = faiss.IndexFlatL2(d)
         index = faiss.IndexIVFPQ(quantizer, d, ncentroids, M, 8)
-        index.nprobe = 12
+        index.nprobe = 20
 
         res = ev.launch("IVFPQ", index)
         e_ivfpq = ev.evalres(res)
 
         quantizer = faiss.IndexFlatL2(d)
         index_ivfpq = faiss.IndexIVFPQ(quantizer, d, ncentroids, M, 8)
-        index_ivfpq.nprobe = 12
+        index_ivfpq.nprobe = 20
         opq_matrix = faiss.OPQMatrix(d, M)
         opq_matrix.niter = 10
         index = faiss.IndexPreTransform(opq_matrix, index_ivfpq)