tree-optimization/113475 - fix memory leak in phi_analyzer

tree-optimization/113475 - fix memory leak in phi_analyzer

phi_analyzer leaks all phi_group objects it allocates.  The following
fixes this by maintaining a vector of allocated objects and release
them when destroying the phi_analyzer object.

	PR tree-optimization/113475
	* gimple-range-phi.h (phi_analyzer::m_phi_groups): New.
	* gimple-range-phi.cc (phi_analyzer::phi_analyzer): Initialize.
	(phi_analyzer::~phi_analyzer): Deallocate and free collected
	phi_grous.
	(phi_analyzer::process_phi): Record allocated phi_groups.