Revert "Add UWP support to Windows toolchain."

This reverts commit 97c38202.

Reason for revert: miscompiles seen in crbug.com/1045948

Original change's description:
> Add UWP support to Windows toolchain.
> 
> Slight update to MSVC - VS version from 16.3.1 to 16.4.3 as a side effect.
> Other components kept at the old versions:
> Windows SDK 10.0.18362
> Debuggers 10.0.17763
> d3dcompiler_47.dll 10.0.17134
> 
> Packaging was done on a Windows Server 2019 VM, cleanly created for this
> purpose.
> 
> The package was created by downloading VS Professional 2019 installer
> from https://visualstudio.microsoft.com/downloads/
> and then running the installer like this:
> 
> $ PATH_TO_INSTALLER.EXE ^
>     --add Microsoft.VisualStudio.Workload.NativeDesktop ^
>     --add Microsoft.VisualStudio.Component.VC.ATLMFC ^
>     --add Microsoft.VisualStudio.Component.VC.Tools.ARM64 ^
>     --add Microsoft.VisualStudio.Component.VC.MFC.ARM64 ^
>     --includeRecommended --passive
> 
> The 10.0.18362.0 SDK was installed by this as well.
> Then Add or Remove Programs was used to modify the 10.0.18362.0 SDK to add
> the Debuggers package.
> 
> Then the packaging script was run like this:
> 
>   python depot_tools\win_toolchain\package_from_installed.py 2019 -w 10.0.18362.0
> 
> Since the new d3dcompiler_47.dll uses the UCRT and we want to avoid shipping
> that the final packaging step was to unzip the package, copy over the two copies
> of that DLL from win_sdk\Redist, replace the Debuggers directory with the
> 10.0.17763 SDK, and then repackage the toolchain with:
>   > python package_from_installed.py --repackage=<full-path-to-toolchain-dir>
> 
> UWP support was previously added to package_from_installed.py
> in http://crrev.com/c/2007881 and http://crrev.com/c/2013579
> 
> Bug: 1032635
> Change-Id: I85313de0529aa7591e5066bc697c640c5dc52463
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2015984
> Reviewed-by: Nico Weber <thakis@chromium.org>
> Commit-Queue: Yuly Novikov <ynovikov@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#734608}

TBR=thakis@chromium.org,ynovikov@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 1032635
Change-Id: Ib3caeaab51cbc4c133955585c5ab4ba69ac480de
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2022357Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#735479}

build/vs_toolchain.py

@@ -423,13 +423,12 @@ def _GetDesiredVsToolchainHashes():
   * //docs/windows_build_instructions.md mentions of VS or Windows SDK.
     Keeps the document consistent with the toolchain version.
   """
-  # VS 2019 version 16.4.3 (16.4.29709.97) with 10.0.18362 SDK,
-  # 10.0.17763 version of Debuggers,
-  # and 10.0.17134 version of d3dcompiler_47.dll,
-  # with ARM64 libraries and UWP support.
+  # VS 2019 Update 9 (16.3.29324.140) with 10.0.18362 SDK, 10.0.17763 version of
+  # Debuggers, and 10.0.17134 version of d3dcompiler_47.dll, with ARM64
+  # libraries.
   # See go/chromium-msvc-toolchain for instructions about how to update the
   # toolchain.
-  toolchain_hash = 'b92fff97f2e0323e99803f37f4b77b843bdbf69d'
+  toolchain_hash = '8f58c55897a3282ed617055775a77ec3db771b88'
   # Third parties that do not have access to the canonical toolchain can map
   # canonical toolchain version to their own toolchain versions.
   toolchain_hash_mapping_key = 'GYP_MSVS_HASH_%s' % toolchain_hash