std.cfg: snprintf(NULL,0,) is legal. Fix some testcases in test/cfg as well

cfg/std.cfg

@@ -5298,11 +5298,6 @@
     <noreturn>false</noreturn>
     <leak-ignore/>
     <formatstr/>
-    <arg nr="1">
-      <not-null/>
-      <minsize type="argvalue" arg="2"/>
-      <minsize type="strlen" arg="3"/>
-    </arg>
     <arg nr="2">
       <not-uninit/>
     </arg>

samples/outOfBounds/bad.c

@@ -2,5 +2,5 @@
 int main()
 {
     char str[5];
-    snprintf(str, 10, "%s", "0123456789abcdef");
+    strcpy(str, "0123456789abcdef");
 }

test/cfg/posix.c

@@ -143,9 +143,6 @@ void uninitvar(int fd) {
     pattern="";
     // cppcheck-suppress uninitvar
     regcomp(&reg, pattern, cflags);
-    cflags=42;
-    // cppcheck-suppress uninitvar
-    regcomp(&reg, pattern, cflags);
 }
 
 void uninitvar_types(void) {

test/cfg/std.c

@@ -21,8 +21,7 @@ void bufferAccessOutOf(void) {
   // cppcheck-suppress bufferAccessOutOfBounds
   sprintf(a, "ab%s", "cde");
   snprintf(a, 5, "abcde%i", 1);
-  // cppcheck-suppress bufferAccessOutOfBounds
-  snprintf(a, 6, "abcde%i", 1);
+  snprintf(a, 6, "abcde%i", 1);   //TODO: cppcheck-suppress bufferAccessOutOfBounds
   strcpy(a,"abcd");
   // cppcheck-suppress bufferAccessOutOfBounds
   strcpy(a, "abcde");
@@ -126,6 +125,10 @@ void nullpointer(int value){
   strxfrm(0,"foo",0);
   // TODO: error message
   strxfrm(0,"foo",42);
+  
+  snprintf(NULL, 0, "someformatstring"); // legal
+  // cppcheck-suppress nullPointer
+  snprintf(NULL, 42, "someformatstring"); // not legal
 }
 
 void nullpointerMemchr1(char *p, char *s) {