types\optional_test.cc compilation issue with Visual Studio 2017 (v15.8)

# Description
When trying to do a CMake-based build with test of abseil-cpp, I got an compile error on
types\optional_test.cc

note: I've applied the PR #194 (absl::container similar issue?) and #196 (alignment conformance) and PR #197 (CI cmake jobs)

```shell
optional_test.cc
Building Custom Rule C:/projects/abseil-cpp/absl/debugging/CMakeLists.txt
exception_safety_testing.cc
CMake does not need to re-run because C:/projects/abseil-cpp/build/absl/debugging/CMakeFiles/generate.stamp is up-to-date.
c:\projects\abseil-cpp\absl\types\optional_test.cc(1108): fatal error C1001: An internal error has occurred in the compiler. [C:\projects\abseil-cpp\build\absl\types\optional_test_bin.vcxproj]
(compiler file 'msc1.cpp', line 1518)
To work around this problem, try simplifying or changing the program near the locations listed above.
Please choose the Technical Support command on the Visual C++
Help menu, or open the Technical Support help file for more information
Internal Compiler Error in C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\bin\HostX86\x64\CL.exe. You will be prompted to send an error report to Microsoft later.
```
Full Appveyor-CI log line 708:
https://ci.appveyor.com/project/Mizux/abseil-cpp/builds/19632736/job/thal0yvy6dacd9e0

The code optional_test.cc in the error log:
https://github.com/abseil/abseil-cpp/blob/2019e17a520575ab365b2b5134d71068182c70b8/absl/types/optional_test.cc#L990-L1058