v0.0-879-g181c8f3: PR #644: Verify gcc and g++ version in Kokoro kythe build.

Also remove unused code.

This is an attempt to debug the Kokoro kythe build that is consistently not working [[1]](https://source.cloud.google.com/results/invocations/74ae259f-e375-42c1-a1f5-76d6c99ad49a/targets/foss-fpga-tools%2Fverible_internal%2Fkythe_index_generation/log). It looks like it is using some old compiler or old libstdc++ which results in some of the compile troubles ? At least the compile error messages that reference `usr/include/c++/5/` are suspicious.

So as first step, let's output the gcc version.

Also, while at it, remove some old bazel install code.

GitHub PR https://github.com/google/verible/pull/644

Copybara import of the project:

  - 3b0791d8635cc6ee7c9f6c2fc44578a10e8e8755 Verify gcc and g++ version in Kokoro kythe build. by Henner Zeller <[email protected]>
  - 7242ea3897a9b954951661d7beb6ea5167342cf9 Merge 3b0791d8635cc6ee7c9f6c2fc44578a10e8e8755 into 58e17... by Henner Zeller <[email protected]>

Closes #644

PiperOrigin-RevId: 351744957