YT-19324: move YT provider to ydb/library/yql

This commit is formed by the following script: https://paste.yandex-team.ru/6f92e4b8-efc5-4d34-948b-15ee2accd7e7/text.
This commit has zero effect on all projects that depend on YQL.

The summary of changes:
- `yql/providers/yt -> ydb/library/yql/providers/yt `- the whole implementation of YT provider is moved into YDB code base for further export as a part of YT YQL plugin shared library;
- `yql/providers/stat/{expr_nodes,uploader} -> ydb/library/yql/providers/stat/{expr_nodes,uploader}` - a small interface without implementation and the description of stat expr nodes;
- `yql/core/extract_predicate/ut -> ydb/library/yql/core/extract_predicate/ut`;
- `yql/core/{ut,ut_common} -> ydb/library/yql/core/{ut,ut_common}`;
- `yql/core` is gone;
- `yql/library/url_preprocessing -> ydb/library/yql/core/url_preprocessing`.

**NB**: all new targets inside `ydb/` are under `IF (NOT CMAKE_EXPORT)` clause which disables them from open-source cmake generation and ya make build. They will be enabled in the subsequent commits.

1 files changed, 48 insertions, 0 deletions

diff --git a/library/cpp/yt/threading/unittests/spin_wait_ut.cpp b/library/cpp/yt/threading/unittests/spin_wait_ut.cpp
new file mode 100644
index 0000000000..8469634f34
--- /dev/null
+++ b/library/cpp/yt/threading/unittests/spin_wait_ut.cpp
@@ -0,0 +1,48 @@
+#include <library/cpp/testing/gtest/gtest.h>
+
+#include <library/cpp/yt/threading/spin_wait.h>
+#include <library/cpp/yt/threading/spin_wait_hook.h>
+
+#include <thread>
+#include <mutex>
+
+namespace NYT::NThreading {
+namespace {
+
+////////////////////////////////////////////////////////////////////////////////
+
+bool SpinWaitSlowPathHookInvoked;
+
+void SpinWaitSlowPathHook(
+    TCpuDuration cpuDelay,
+    const TSourceLocation& /*location*/,
+    ESpinLockActivityKind /*activityKind*/)
+{
+    SpinWaitSlowPathHookInvoked = true;
+    auto delay = CpuDurationToDuration(cpuDelay);
+    EXPECT_GE(delay, TDuration::Seconds(1));
+    EXPECT_LE(delay, TDuration::Seconds(5));
+}
+
+TEST(TSpinWaitTest, SlowPathHook)
+{
+    static std::once_flag registerFlag;
+    std::call_once(
+        registerFlag,
+        [] {
+            RegisterSpinWaitSlowPathHook(SpinWaitSlowPathHook);
+        });
+    SpinWaitSlowPathHookInvoked = false;
+    {
+        TSpinWait spinWait(__LOCATION__, ESpinLockActivityKind::ReadWrite);
+        for (int i = 0; i < 1'000'000; ++i) {
+            spinWait.Wait();
+        }
+    }
+    EXPECT_TRUE(SpinWaitSlowPathHookInvoked);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace
+} // namespace NYT::NThreading