amd64 and arm don't pass floats on the stack

Shifting more than variable width adds zeros on ARM to fill up.

Without the memset() there is a risk of leaking uninitialized stack memory in the
get_next_device_request wineserver call.

BindToObject fails in this case.

ieframe: Properly test events when container doesn't support IOleCommandTarget add added more tests.

ieframe: Use stored IOleCommandTarget in Exec implementation and get rid of no longer needed exec in IDocHostContainerVtbl.