Minimize clone counter memory usage in create_virtual_clone.

Minimize clone counter memory usage in create_virtual_clone.

Based on Martin Jambour's suggestion:
https://gcc.gnu.org/ml/gcc-patches/2018-09/msg00111.html

gcc:

	* cgraph.h (clone_function_name): Add a variant that takes a
	tree decl.
	* cgraph.h (cgraph_node::create_virtual_clone): Add a new
	argument: num_suffix.
	* cgraphclones.c (cgraph_node::create_virtual_clone): Pass
	num_suffix to clone_function_name.
	(clone_function_name): Add a variant that takes a tree decl.
	* ipa-cp.c (create_specialized_node): Keep track of clone
	counters in clone_num_suffixes hash map.
	(ipcp_driver): Free the counter hash map.
	* ipa-hsa.c (process_hsa_functions): Creates at most one hsa
	clone per function.

From-SVN: r266692