unit_thread_pool.cc: add forgotten <random> include (#4690)

At least when building with `gcc` this source needs to include
`<random>`, otherwise it fails to compile.

---
TYPE: NO_HISTORY
DESC: Add a missing include into `unit_thread_pool.cc`

---------

Co-authored-by: Theodore Tsirpanis <[email protected]>

Author: barracuda156

test/src/unit-tile-metadata-generator.cc

@@ -30,6 +30,8 @@
  * Tests the TileMetadataGenerator class.
  */
 
+#include <random>
+
 #include <test/support/tdb_catch.h>
 #include "test/support/src/helpers.h"
 #include "tiledb/common/common.h"

test/src/unit-tile-metadata.cc

@@ -31,6 +31,8 @@
  * load_tile_*_values and get_tile_* apis of fragment metadata.
  */
 
+#include <random>
+
 #include <test/support/tdb_catch.h>
 #include "test/support/src/helpers.h"
 #include "tiledb/sm/c_api/tiledb_struct_def.h"

tiledb/common/thread_pool/test/unit_thread_pool.cc

@@ -37,6 +37,7 @@
 #include <atomic>
 #include <cstdio>
 #include <iostream>
+#include <random>
 #include <vector>
 
 #include "tiledb/common/thread_pool.h"

tiledb/sm/query/readers/aggregators/test/bench_aggregators.cc

@@ -30,6 +30,8 @@
  * Benchmarks the `AggregateWithCount` class.
  */
 
+#include <random>
+
 #include "tiledb/common/common.h"
 #include "tiledb/sm/query/readers/aggregators/aggregate_buffer.h"
 #include "tiledb/sm/query/readers/aggregators/aggregate_with_count.h"