Revert "Dawn: use Dawn's temporary test targets for isolates."

This reverts commit 74d46702b56909ad86778c5228257a71095b69e1.

Reason for revert: Seems to be causing build breakage: https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Deterministic%20Linux

Original change's description:
> Dawn: use Dawn's temporary test targets for isolates.
> 
> The plan is to move the actual test targets in Dawn to Dawn's
> src/test directory. This change makes Chrome temporarily point at
> some intermediate proxy targets, so we can move the real ones
> without breaking Chrome.
> 
> Bug: dawn:61
> Change-Id: I166c17f1689e2a2e71b1607af44f6f9a8c14b6af
> Reviewed-on: https://chromium-review.googlesource.com/c/1372709
> Reviewed-by: Nico Weber <thakis@chromium.org>
> Commit-Queue: Stephen White <senorblanco@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#615715}

TBR=thakis@chromium.org,senorblanco@chromium.org,cwallez@chromium.org

Change-Id: Iec9120066c23710c4b2dbe22a50813a23ad299a2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: dawn:61
Reviewed-on: https://chromium-review.googlesource.com/c/1372107
Reviewed-by: Alice Boxhall <aboxhall@chromium.org>
Commit-Queue: Alice Boxhall <aboxhall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#615743}
1 file changed