Disable SitePerProcessBrowserTest.SurfaceHitTestTest for Linux.
Disable SitePerProcessBrowserTest.SurfaceHitTestTest for Linux.

It has become flaky recently.

BUG=528189
TBR=lukasza@chromium.org

Review URL: https://codereview.chromium.org/1304893009

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#347386}

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