Enable running spec tests on Windows (#2423)

Update wamr-test-suites scripts to enable running spec tests on Windows.
We don't enable those tests in CI yet as not all of them are passing.

product-mini/platforms/windows/main.c

@@ -142,7 +142,8 @@ app_instance_repl(wasm_module_inst_t module_inst)
     char *cmd;
     size_t n;
 
-    while ((printf("webassembly> "), cmd = fgets(buffer, sizeof(buffer), stdin))
+    while ((printf("webassembly> "), fflush(stdout),
+            cmd = fgets(buffer, sizeof(buffer), stdin))
            != NULL) {
         bh_assert(cmd);
         n = strlen(cmd);