Revert "temporary disable DP MT benchmark"

This reverts commit 604b870.

Author: bratpiorka

benchmark/benchmark.cpp

@@ -89,9 +89,8 @@ UMF_BENCHMARK_TEMPLATE_DEFINE(multiple_malloc_free_benchmark,
                               disjoint_pool_uniform, uniform_alloc_size,
                               pool_allocator<disjoint_pool<os_provider>>);
 UMF_BENCHMARK_REGISTER_F(multiple_malloc_free_benchmark, disjoint_pool_uniform)
-    ->Apply(&default_multiple_alloc_uniform_size);
-// TODO: enable
-//->Apply(&multithreaded);
+    ->Apply(&default_multiple_alloc_uniform_size)
+    ->Apply(&multithreaded);
 
 #ifdef UMF_POOL_JEMALLOC_ENABLED
 UMF_BENCHMARK_TEMPLATE_DEFINE(multiple_malloc_free_benchmark, jemalloc_pool_fix,