Remove unused parameters from test code.

test/product/hello.c

Index: test/product/hello.c
diff --git a/test/product/hello.c b/test/product/hello.c
index 94798f3e751d0a94d5556198b4861d4d3b432b0b..b6d351feb25b13a98740f107a51c5eb50cd61b02 100644
--- a/test/product/hello.c
+++ b/test/product/hello.c
@@ -8,7 +8,7 @@ int func1(void) {
   return 42;
 }
 
-int main(int argc, char *argv[]) {
+int main() {
   printf("Hello, world!\n");
   printf("%d\n", func1());
   return 0;