Add s_variable_scale_2x solver (Task 307, 262/262) to wave5.py + register in solver_registry"

own-solver/WAVE5_REGISTRY_ENTRIES.txt

@@ -0,0 +1,7 @@
+    ('row_uniform_fill', s_row_uniform_fill),
+    ('majority_replace_5', s_majority_replace_5),
+    ('find_color_with_hole', s_find_color_with_hole),
+    ('fill_bbox_per_color', s_fill_bbox_per_color),
+    ('border_detect', s_border_detect),
+    ('symmetry_check_lr', s_symmetry_check_lr),
+    ('variable_scale_2x', s_variable_scale_2x),