Have test results log report the actual php version it used

Problem/Motivation

Test results have a few different places where php version might be reported.

On test results, for example: https://qa.drupal.org/pifr/test/816338

The test env name (for drupal 8) is: PHP 5.4 MySQL
(for drupal 7 it is: MySQL)

Also in expanding the "Review log" at the bottom of test results:
[phpversion] => 5.4
[test.php.version] => 5.4

But sometimes, minor versions matter.

On qa.drupal.org there is a block on the left:
Alternate Environment (PHP/DB) Test Results ... those are different ...

Proposed resolution

Report the exact version of php used when a test was run.
For example: 5.4.4

Remaining tasks

• get more info from people who know about testbot details
• move to the specific issue queue

User interface changes

?

API changes

NA