testing: display in help possible values for several options

So we don't have to look in the code if we don't know which value to put.

testing/values.c

@@ -165,7 +165,6 @@ val_t pread_uplo( const char *str )
     val.uplo = ChamUpperLower;
 
     /* Keep in sync with help documentation in testing/{chameleon,vendor}_ztesting.c */
-
     if ( ( strcasecmp( "ChamUpper", str ) == 0 ) ||
          ( strcasecmp( "Upper",     str ) == 0 ) )
     {