Googletest export

Remove platformio tests. This currently uses gcc 4.8.2 which is no
longer supported.

PiperOrigin-RevId: 351667999

.travis.yml

@@ -9,10 +9,6 @@ language: cpp
 # It is more tedious, but grants us far more flexibility.
 matrix:
   include:
-    - os: linux
-      before_install: chmod -R +x ./ci/*platformio.sh
-      install: ./ci/install-platformio.sh
-      script: ./ci/build-platformio.sh
     - os: linux
       dist: bionic
       compiler: gcc