Fix VS15 toolchain configure: hide output from VsDevCmd.bat
Fix VS15 toolchain configure: hide output from VsDevCmd.bat

VsDevCmd.bat outputs header
```
**********************************************************************
** Visual Studio 2019 Developer Command Prompt v16.3.10
** Copyright (c) 2019 Microsoft Corporation
**********************************************************************
```
which interferes with
```
echo %VCINSTALLDIR%
```
and doesn't allow to configure VS toolchain.

Closes #10321.

PiperOrigin-RevId: 282910056

meteorcloudy/bazel,davidzchen/bazel,twitter-forks/bazel,ButterflyNetwork/bazel,cushon/bazel,ulfjack/bazel,ButterflyNetwork/bazel,dslomov/bazel-windows,ulfjack/bazel,twitter-forks/bazel,akira-baruah/bazel,davidzchen/bazel,katre/bazel,ulfjack/bazel,davidzchen/bazel,akira-baruah/bazel,safarmer/bazel,davidzchen/bazel,meteorcloudy/bazel,safarmer/bazel,akira-baruah/bazel,bazelbuild/bazel,akira-baruah/bazel,twitter-forks/bazel,safarmer/bazel,perezd/bazel,akira-baruah/bazel,safarmer/bazel,dslomov/bazel-windows,meteorcloudy/bazel,perezd/bazel,perezd/bazel,werkt/bazel,dslomov/bazel-windows,bazelbuild/bazel,bazelbuild/bazel,ulfjack/bazel,cushon/bazel,safarmer/bazel,werkt/bazel,dslomov/bazel,bazelbuild/bazel,katre/bazel,werkt/bazel,dslomov/bazel-windows,katre/bazel,twitter-forks/bazel,ButterflyNetwork/bazel,dslomov/bazel,dslomov/bazel,davidzchen/bazel,davidzchen/bazel,dslomov/bazel-windows,werkt/bazel,perezd/bazel,dslomov/bazel,ButterflyNetwork/bazel,dslomov/bazel,dslomov/bazel,ulfjack/bazel,meteorcloudy/bazel,dslomov/bazel,bazelbuild/bazel,werkt/bazel,cushon/bazel,perezd/bazel,katre/bazel,perezd/bazel,twitter-forks/bazel,ulfjack/bazel,katre/bazel,twitter-forks/bazel,bazelbuild/bazel,perezd/bazel,meteorcloudy/bazel,katre/bazel,ButterflyNetwork/bazel,dslomov/bazel-windows,cushon/bazel,safarmer/bazel,davidzchen/bazel,meteorcloudy/bazel,akira-baruah/bazel,ulfjack/bazel,cushon/bazel,cushon/bazel,werkt/bazel,ButterflyNetwork/bazel,twitter-forks/bazel,meteorcloudy/bazel