esp32: Fix not the right time spent in a deep sleep

Before entering the deep sleep, the RTC and FRC counters are synchronized. Updating the boot_time.
Added a unit test for this case.
Fixed warnings for MULTIPLE_STAGES

Closes https://github.com/espressif/esp-idf/issues/1840

components/esp32/sleep_modes.c

@@ -203,7 +203,7 @@ void IRAM_ATTR esp_deep_sleep_start()
 {
     // record current RTC time
     s_config.rtc_ticks_at_sleep_start = rtc_time_get();
-
+    esp_sync_counters_rtc_and_frc();
     // Configure wake stub
     if (esp_get_deep_sleep_wake_stub() == NULL) {
         esp_set_deep_sleep_wake_stub(esp_wake_deep_sleep);