Fix incorrect argument in 'do_size' error message

Previously, the error message in 'do_size' referenced 'argv[2]' instead
of 'argv[1]'. Since 'argc' is at most 2 in this context, 'argv[2]' is
always null, as defined in Section 5.1.2.2.1 of the C11 standard. While
GCC prints "(null)" for a null pointer in '%s' formatting, this behavior
is implementation-defined. Other compilers may cause undefined behavior,
potentially leading to a segmentation fault.

This change ensures the correct argument is used, avoiding reliance on
implementation-specific behavior and preventing potential crashes.

Change-Id: I27748efd7c3d533659a6eda78f7c68ced2e78366

Author: Dennis40816

qtest.c

@@ -544,7 +544,7 @@ static bool do_size(int argc, char *argv[])
     bool ok = true;
     if (argc == 2) {
         if (!get_int(argv[1], &reps))
-            report(1, "Invalid number of calls to size '%s'", argv[2]);
+            report(1, "Invalid number of calls to size '%s'", argv[1]);
     }
 
     int cnt = 0;