Delete tools/whitespace.txt.

This was only added to work around crbug.com/416124 and is no longer needed,
and apparenty it's causing issues on the gpu bots.

BUG=none
TBR=hans

Review URL: https://codereview.chromium.org/586163002

Cr-Commit-Position: refs/heads/master@{#295776}

tools/whitespace.txt

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