The generated code contained many repeated blank lines.
Most main()s were preceded by one, but not all.
Only include blank lines for actual empty entries in lists, where
configure.json specified them, plus one before main if anything else
precedes it.
Change-Id: I6e6c34940e08712a1aa848a3c9ad1b0fb5806d77
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>