Revert of Disable Precompile-platform with clang-cl.

Revert of Disable Precompile-platform with clang-cl. (patchset #1 id:1 of https://codereview.chromium.org/2520833005/ )

Reason for revert:
The crash is now hopefully fixed in clang-cl.

Original issue's description:
> Disable Precompile-platform with clang-cl.
>
> It currently asserts while trying to build that PCH file.
>
> BUG=667891, 495697
> NOTRY=true
>
> Committed: https://crrev.com/5b7b04e7fa59d53b8b7917d4c0cf4081abdfb0e3
> Cr-Commit-Position: refs/heads/master@{#434028}

TBR=rnk@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=667891, 495697
Committed: https://crrev.com/a0eb8ed36a1c3e2c5becc95ef03d42655c7cd95c
Cr-Commit-Position: refs/heads/master@{#434534}

[Nico, 2016-11-24 20:20:48]

The CQ bit was checked by thakis@chromium.org

[Nico, 2016-11-24 20:20:48]

Created Revert of Disable Precompile-platform with clang-cl.

[commit-bot: I haz the power, 2016-11-24 20:20:59]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-24 21:08:49]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-24 21:08:51]

Try jobs failed on following builders:
  linux_chromium_chromeos_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[Nico, 2016-11-25 16:46:48]

The CQ bit was checked by thakis@chromium.org

[commit-bot: I haz the power, 2016-11-25 16:47:05]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-11-25 17:32:13]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1480092408987020, "parent_rev":
"2aba817318a9100d541a636d14b04c1027e6bcc9", "commit_rev":
"497e8f39a26cc23feb9aca7422509804c1d70e56"}

[commit-bot: I haz the power, 2016-11-25 17:32:39]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-11-25 17:34:29]

Description was changed from

==========
Revert of Disable Precompile-platform with clang-cl. (patchset #1 id:1 of
https://codereview.chromium.org/2520833005/ )

Reason for revert:
The crash is now hopefully fixed in clang-cl.

Original issue's description:
> Disable Precompile-platform with clang-cl.
> 
> It currently asserts while trying to build that PCH file.
> 
> BUG=667891,495697
> NOTRY=true
> 
> Committed: https://crrev.com/5b7b04e7fa59d53b8b7917d4c0cf4081abdfb0e3
> Cr-Commit-Position: refs/heads/master@{#434028}

TBR=rnk@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=667891,495697
==========

to

==========
Revert of Disable Precompile-platform with clang-cl. (patchset #1 id:1 of
https://codereview.chromium.org/2520833005/ )

Reason for revert:
The crash is now hopefully fixed in clang-cl.

Original issue's description:
> Disable Precompile-platform with clang-cl.
>
> It currently asserts while trying to build that PCH file.
>
> BUG=667891,495697
> NOTRY=true
>
> Committed: https://crrev.com/5b7b04e7fa59d53b8b7917d4c0cf4081abdfb0e3
> Cr-Commit-Position: refs/heads/master@{#434028}

TBR=rnk@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=667891,495697

Committed: https://crrev.com/a0eb8ed36a1c3e2c5becc95ef03d42655c7cd95c
Cr-Commit-Position: refs/heads/master@{#434534}
==========

[commit-bot: I haz the power, 2016-11-25 17:34:29]

Patchset 1 (id:??) landed as
https://crrev.com/a0eb8ed36a1c3e2c5becc95ef03d42655c7cd95c
Cr-Commit-Position: refs/heads/master@{#434534}

[Reid Kleckner, 2016-11-28 19:57:56]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/2533853003/ by rnk@chromium.org.

The reason for reverting is: Clang still asserts when building
Precompile-core.obj, but it's somewhere else:
Assertion failed: AllowUnresolvedNodes && "Cannot handle unresolved nodes"....