Add ref test for verifying colored clear behavior

This covers the behavior of clearing the screen and a row with colored
cells.

This covers a bug discovered in #2329 which was not detected in any
existing ref tests.

alacritty_terminal/tests/ref.rs

@@ -53,6 +53,7 @@ ref_tests! {
     row_reset
     zerowidth
     selective_erasure
+    colored_reset
 }
 
 fn read_u8<P>(path: P) -> Vec<u8>

alacritty_terminal/tests/ref/colored_reset/alacritty.recording

@@ -0,0 +1,3 @@
+[undeadleech@archhq colored_reset]$ printf "\e[41m"
+[undeadleech@archhq colored_reset]$ [undeadleech@archhq colored_reset]$ printf "\e[0m"
+[undeadleech@archhq colored_reset]$ ls -

alacritty_terminal/tests/ref/colored_reset/config.json

@@ -0,0 +1 @@
+{"history_size":0}

alacritty_terminal/tests/ref/colored_reset/size.json

@@ -0,0 +1 @@
+{"width":939.0,"height":1020.0,"cell_width":8.0,"cell_height":16.0,"padding_x":5.0,"padding_y":6.0,"dpr":1.0}