Decrease amount of code duplication regarding handling of safecall and record constructors.

paramgr.pas, tparamanager:
    + add new method "handle_common_ret_in_param"
    * extract common code (safecall + record constructor handling) from "ret_in_param" to "handle_common_ret_in_param" and call the latter in "ret_in_param"
[aarch64,arm,avr,i386,x86_64]/cpupara.pas, tCPUparamanager.ret_in_param:
    * call "handle_common_ret_in_param" instead of implementing the same check again and again
ncgcal.pas, tcgcallnode.handle_return_value:
    * move the check for (record) constructors to "tparamanager.handle_common_ret_in_param"


git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@23520 3ad0048d-3df7-0310-abae-a5850022a9f2