add some code

managed_components/espressif__esp-dsp/modules/fft/test_sim/main.c

@@ -0,0 +1,14 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+void test_fft2r();
+
+int main(void)
+{
+    printf("main starts!\n");
+//    xt_iss_profile_enable();
+    test_fft2r();
+//    xt_iss_profile_disable();
+
+    printf("Test done\n");
+}