azrp: fix a cmdgen bug causing crashes when buffer is full

Command finalization could refuse to finalize commands that were
allocated, because its rounding method added 4 extra bytes to commands
whose size is a multiple of 4. Such commands would still be instantiated
but without commands_length advancing, causing the underlying memory to
be reallocated later, leading to overlapping commands.

azur/src/gint/render.c

@@ -300,7 +300,7 @@ void *azrp_alloc_command(size_t size, int *extra, int count)
 void azrp_finalize_command(void const *command, int total_size)
 {
     (void)command;
-    total_size = (total_size | 3) + 1;
+    total_size = (total_size + 3) & -4;
 
     if(commands_length + total_size > (int)sizeof commands_data)
         return;

azur/src/gint/shaders/triangle.c

@@ -64,7 +64,7 @@ void azrp_triangle(int x1, int y1, int x2, int y2, int x3, int y3, int color)
     int min_y = max(0, min(y1, min(y2, y3)));
     int max_y = min(azrp_height-1, max(y1, max(y2, y3)));
 
-    if(min_x >= max_x || min_y >= max_y) {
+    if(min_x > max_x || min_y > max_y) {
         prof_leave(azrp_perf_cmdgen);
         return;
     }