Delete TESTS files in chrome/tools/build/

according to previous git log[1],
it looks likes used to store test files
in official Chrome build gs:// drops.
these files haven't been touched in a long time.
and it seems like not used any more.

[1]https://codereview.chromium.org/545103003

Bug: 829975
Change-Id: Ida8e887c64d4d18b7eb877f3cda2001a1871b844
Reviewed-on: https://chromium-review.googlesource.com/1027598Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Hwanseung Lee <hwanseung@chromium.org>
Cr-Commit-Position: refs/heads/master@{#553915}

chrome/tools/build/chromeos/TESTS

-ffmpeg_tests

chrome/tools/build/linux/TESTS

-interactive_ui_tests
-browser_tests
-sync_integration_tests

chrome/tools/build/mac/TESTS

-sync_integration_tests

chrome/tools/build/win/TESTS

-test_shell.exe
-interactive_ui_tests.exe
-icudt38.dll
-icudt42.dll
-icudt46.dll
-icudt.dll
-icudtl.dat
-fonts\*