Merge branch 'refine_pq_unittest' into 'branch-0.5.0'

MS-657 Refine PQ unittest time

See merge request megasearch/milvus!727

Former-commit-id: db446534866d9627d7803a506559c58ef7986a90

core/src/index/unittest/test_ivf.cpp

@@ -96,10 +96,10 @@ class ParamGenerator {
             auto tempconf = std::make_shared<knowhere::IVFPQCfg>();
             tempconf->d = DIM;
             tempconf->gpu_id = device_id;
-            tempconf->nlist = 100;
-            tempconf->nprobe = 16;
+            tempconf->nlist = 25;
+            tempconf->nprobe = 4;
             tempconf->k = K;
-            tempconf->m = 8;
+            tempconf->m = 4;
             tempconf->nbits = 8;
             tempconf->metric_type = knowhere::METRICTYPE::L2;
             return tempconf;