Rename inchash::hash::add_wide_int

Rename inchash::hash::add_wide_int

The name inchash::add_wide_int is a bit misleading, since it sounds
like it's hashing a wide_int.  This patch renames it to add_hwi instead.

2017-10-22  Richard Sandiford  <richard.sandiford@linaro.org>

gcc/
	* inchash.h (inchash::hash::add_wide_int): Rename to...
	(inchash::hash::add_hwi): ...this.
	* ipa-devirt.c (hash_odr_vtable): Update accordingly.
	(polymorphic_call_target_hasher::hash): Likewise.
	* ipa-icf.c (sem_function::get_hash, sem_function::init): Likewise.
	(sem_item::add_expr, sem_item::add_type, sem_variable::get_hash)
	(sem_item_optimizer::update_hash_by_addr_refs): Likewise.
	* lto-streamer-out.c (hash_tree): Likewise.
	* optc-save-gen.awk: Likewise.
	* tree.c (add_expr): Likewise.

From-SVN: r253987