Add gtest_force_shared_crt for MSVC

[meastp]

No description provided.

[g-easy]

Please describe why this is being done.

[meastp]

This is being done simply because the build (or, to be more specifik, the linking) on MSVC fails when abseil and opencensus-cpp compile with /MD, and googletest compiles with /MT.

  # force this option to ON so that Google Test will use /MD instead of /MT
# /MD is now the default for Visual Studio, so it should be our default, too

[g-easy]

Makes sense. Thanks a lot for the followup. Please run tools/format.sh

[meastp]

I'm on Windows, so I can not run tools/format.sh directly, but by reading the script I think only the following applies to my changes (I'm not familiar with the buildify command, so I don't know if it applies):

No CRLF line endings.

sed -i 's/\r$//' $($FIND -type f -print)

No trailing spaces.

sed -i 's/ +$//' $($FIND -type f -print)

If this is correct I'll fix that. Please confirm that my understanding is correct... :)

[g-easy]

Those definitely apply, but cmake-format might be in play for this PR as well.

[g-easy]

It's not just whitespace. I did the format on my end but I don't think I can push it to this PR:

git checkout -b meastp-meastp_msvc_add_gtest_force_shared_crt master
git pull https://github.com/meastp/opencensus-cpp.git meastp_msvc_add_gtest_force_shared_crt
tools/format.sh
git commit -a -m format
git push g-easy meastp-meastp_msvc_add_gtest_force_shared_crt

Please apply this commit to the PR: g-easy@17cc862

[g-easy]

If you prefer, I can try to do it in the online editor. :)

[meastp]

Thanks, I managed to merge your commit online by creating a pull request with compare from your repository (using your meastp_msvc_add_gtest_force_shared_crt-branch, obviously) to my repository :)