[cxx_debugging] Shot-in-the-dark attempt to reduce flakiness

Bug: none
Change-Id: I8c18dcc0c1b4cf61aaaf55531397975c5949c236
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6352838
Commit-Queue: Danil Somsikov <dsv@chromium.org>
Auto-Submit: Philip Pfaffe <pfaffe@chromium.org>
Reviewed-by: Danil Somsikov <dsv@chromium.org>

extensions/cxx_debugging/e2e/MochaRootHooks.ts

@@ -43,6 +43,7 @@ async function beforeAll() {
       `--disable-extensions-except=${EXTENSION_DIR}`,
       `--window-size=${defaultViewport.width + 20, defaultViewport.height + 100}`,
       `--custom-devtools-frontend=${new URL(`${DEVTOOLS_DIR}/front_end`, 'file://').href}`,
+      '--disable-features=RenderDocument',
       '--enable-features=DevToolsVeLogging:testing/true',
     ],
   });