ProcessJobExecutor: handles stdout and stderr separately #99

Job	Run time
Coding standard (ubuntu-latest, 8.1)	28s
Static analysis (ubuntu-latest, 8.1)	19s
Tests (ubuntu-latest, 7.4, false)	34s
Tests (ubuntu-latest, 8.0, false)	27s
Tests (ubuntu-latest, 8.1, false)	23s
Test for mutants (ubuntu-latest, 8.1)	1m 26s
Tests (macos-latest, 7.4, false)	1m 23s
Tests (macos-latest, 8.0, false)	1m 27s
Tests (macos-latest, 8.1, false)	1m 5s
Tests (windows-latest, 7.4, false)	1m 2s
Tests (windows-latest, 8.0, false)	1m 0s
Tests (windows-latest, 8.1, false)	59s
Tests (ubuntu-latest, 7.4, --prefer-lowest --prefer-stable, false)	23s
Tests (ubuntu-latest, 8.2, --ignore-platform-req=php+, false)	23s
Status check - CI	2s
Code coverage finish	1s
	11m 22s

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