Revert "TT#8635 set umask for files created by docker"

This reverts commit 610a12680b.

Change-Id: If508e72c01d9bc78836a40204e508585d1dc3555

t/Dockerfile

@@ -20,11 +20,6 @@ RUN echo 'prove -I /code/lib -v --color -l --formatter TAP::Formatter::JUnit' >>
 RUN echo 'prove -I /code/lib --color -l' >>/root/.bash_history
 RUN echo './t/testrunner' >>/root/.bash_history
 
-# Create files with mode 666 and folders with mode 777 which
-# allows to delete the temporary files (aka results) for
-# non-root users (like 'jenkins' or 'developer's laptop local user')
-RUN echo 'umask 0' >>/root/.bashrc
-
 WORKDIR /code/
 
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