Fix profile_flush_to_file() state corruption

Fix profile_flush_to_file() state corruption

In write_data_to_file(), do not clear the profile data object's flags.
If the call to this function resulted from profile_flush_to_file(), we
do not want to clear the DIRTY flag, and we especially do not want to
clear the SHARED flag for a data object which is part of
g_shared_trees.  Instead, clear the DIRTY flag in
profile_flush_file_data().

Add a test case to prof_test1 to exercise the bug in unfixed code.
Also modify test1 to abandon the altered profile after flushing it to
a file, to preserve the external behavior of the script before this
fix.

ticket: 8431
target_version: 1.14-next
tags: pullup