Use std::chrono and std::sleep_for instead of usleep

usleep is specific to Linux

Author: aminya

test/native/text-buffer-test.cc

@@ -4,7 +4,8 @@
 #include "text-slice.h"
 #include "regex.h"
 #include <future>
-#include <unistd.h>
+#include <chrono>
+#include <thread>
 
 using std::move;
 using std::pair;
@@ -535,7 +536,7 @@ TEST_CASE("TextBuffer - random edits and queries") {
             Generator rand(seed);
             vector<SnapshotData> results;
             for (uint32_t k = 0; k < 5; k++) {
-              usleep(rand() % 1000);
+              std::this_thread::sleep_for(std::chrono::microseconds(rand() % 1000));
               vector<Point> line_ending_positions;
               for (uint32_t row = 0; row < snapshot->extent().row; row++) {
                 line_ending_positions.push_back({row, snapshot->line_length_for_row(row)});