Temporarily disable DevTools sources test

Follow-up on crrev.com/c/chromium/src/+/1939791

Bug: 1006759
Change-Id: Ia4932f78b0190732c79d1bdf3112a798dfbe9f66
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1940272
Auto-Submit: Tim van der Lippe <tvanderlippe@chromium.org>
Reviewed-by: Paul Lewis <aerotwist@chromium.org>
Commit-Queue: Tim van der Lippe <tvanderlippe@chromium.org>
Cr-Commit-Position: refs/heads/master@{#719582}

third_party/blink/web_tests/TestExpectations

@@ -5906,6 +5906,7 @@ crbug.com/833100 [ Mac ] external/wpt/battery-status/battery-full-manual.https.h
 crbug.com/1006759 http/tests/devtools/sources/debugger-ui/continue-to-location-markers-in-top-level-function.js [ Pass Failure ]
 crbug.com/1006759 http/tests/devtools/sources/debugger-ui/continue-to-location-markers.js [ Pass Failure ]
 crbug.com/1006759 http/tests/devtools/sources/debugger-ui/popover-for-spread-operator.js [ Pass Failure ]
+crbug.com/1006759 http/tests/devtools/editor/php-highlighter.js [ Pass Failure ]
 
 # Disabled for three-way merge after https://crrev.com/c/devtools/devtools-frontend/+/1934218 is submitted
 crbug.com/1006759 http/tests/devtools/modules-load-network.js [ Pass Failure ]