Ignore webcodecs/reconfiguring_encooder.html on linux_layout_tests_layout_ng_disabled

This patch makes "reconfiguring_encooder.html" to ignore
linux_layout_tests_layout_ng_disabled bot because required web codec
is not installed on the bot.

TBR=eugene@chromium.org

Bug: 591099
Change-Id: I8e40737e62b7600e2c7b67fbbc4c0ee76dc4d065
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2557282Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Commit-Queue: Yoshifumi Inoue <yosin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#830523}

third_party/blink/web_tests/FlagExpectations/disable-layout-ng

@@ -740,6 +740,7 @@ crbug.com/591099 virtual/stable/compositing/filters/sw-nested-shadow-overlaps-hw
 
 ### webcodecs/
 crbug.com/591099 webcodecs/basic_video_encoding.html [ Failure ]
+crbug.com/591099 webcodecs/reconfiguring_encooder.html [ Failure ]
 
 # broken by https://chromium-review.googlesource.com/c/chromium/src/+/2392444
 crbug.com/958381 external/wpt/css/css-flexbox/table-as-item-wide-content.html [ Failure ]