[tests] Sleep more than 1s before refreshing accessed time

The cache `accessed` field resolution is 1s, so we
need to sleep a little bit more in order to make
sure that the cache entries we are refreshing will have
a different `accessed` time than the other entries.

test/storage/cache_size.cpp

@@ -6,12 +6,11 @@
 #include <mbgl/util/run_loop.hpp>
 #include <mbgl/util/string.hpp>
 #include <mbgl/util/time.hpp>
+#include <mbgl/util/timer.hpp>
 
 #include <memory>
 #include <random>
 
-#include <unistd.h>
-
 bool tileIsCached(mbgl::SQLiteCache* cache, unsigned id) {
     using namespace mbgl;
 
@@ -184,7 +183,16 @@ TEST_F(Storage, CacheSizePruneLeastAccessed) {
             // entry, that should update the
             // `accessed` time, so it won't get
             // pruned when we need more space.
-            sleep(1);
+            bool done = false;
+
+            util::Timer timer;
+            timer.start(std::chrono::milliseconds(1300),
+                        Duration::zero(),
+                        [&done] { done = true; });
+
+            while (!done) {
+                loop.runOnce();
+            }
 
             EXPECT_TRUE(tileIsCached(&cache, 7));