yield() without panic() can do the right thing in CONT and SYS alike.

Author: dok-net

cores/esp8266/core_esp8266_main.cpp

@@ -113,13 +113,10 @@ extern "C" IRAM_ATTR void esp_schedule() {
 }
 
 extern "C" void __yield() {
+    esp_schedule();
     if (can_yield()) {
-        esp_schedule();
         esp_yield_within_cont();
     }
-    else {
-        panic();
-    }
 }
 
 extern "C" void yield(void) __attribute__ ((weak, alias("__yield")));