Fix non well-formed numeric value with PHP7 issues

[dmonllao]

Different fixes:

• Session size is less than 1KB in some pages now (congrats moodle devs) the java recorder didn't parse correctly these values in bytes
• The change in webapp/classes/properties_reader.php cleans a trailing space

IMPORTANT NOTE FOR THE INTEGRATOR: webapp/classes/test_plan_runs.php changes should be enough as long as we don't compare results recorded before this fix and after, in normal circumstances we only test latest weekly against current integration, so Friday after the release seems the best time to integrate this. We could only avoid the compare previous results thing by updating all previously generated files which would require time. Any opinion?

[danpoltawski]

Thanks David, as discussed in Integration chat, the patch makes the assumption that session size doesn't grow above 1MB. This seems a reasonable tradeoff.

[dmonllao]

Thanks Dan, as discussed in integration team chat rounded session sizes rounded to 0 are returned without a comma, so this solution is not good enough. I will send a further improvement.