icf: Remove unused constructors of sem_function and sem_variable

icf: Remove unused constructors of sem_function and sem_variable

The constructors for sem_function and sem_variable that just
passes the bitmap obstack and NOT the cgraph node was unused
so let's remove it.

gcc/ChangeLog:

	* ipa-icf.cc (sem_function::sem_function): Remove
	the obstack argument version one.
	(sem_variable::sem_variable): Likewise.
	* ipa-icf.h (sem_function): Remove ctor for
	obstack argument only one.
	(sem_variable): Likewise.

Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>