Rename ssa_global_cache to ssa_cache and add has_range

Rename ssa_global_cache to ssa_cache and add has_range

This renames the ssa_global_cache to be ssa_cache.  The original use was
to function as a global cache, but its uses have expanded.  Remove all mention
of "global" from the class and methods.  Also add a has_range method.

	* gimple-range-cache.cc (ssa_cache::ssa_cache): Rename.
	(ssa_cache::~ssa_cache): Rename.
	(ssa_cache::has_range): New.
	(ssa_cache::get_range): Rename.
	(ssa_cache::set_range): Rename.
	(ssa_cache::clear_range): Rename.
	(ssa_cache::clear): Rename.
	(ssa_cache::dump): Rename and use get_range.
	(ranger_cache::get_global_range): Use get_range and set_range.
	(ranger_cache::range_of_def): Use get_range.
	* gimple-range-cache.h (class ssa_cache): Rename class and methods.
	(class ranger_cache): Use ssa_cache.
	* gimple-range-path.cc (path_range_query::path_range_query): Use
	ssa_cache.
	(path_range_query::get_cache): Use get_range.
	(path_range_query::set_cache): Use set_range.
	* gimple-range-path.h (class path_range_query): Use ssa_cache.
	* gimple-range.cc (assume_query::assume_range_p): Use get_range.
	(assume_query::range_of_expr): Use get_range.
	(assume_query::assume_query): Use set_range.
	(assume_query::calculate_op): Use get_range and set_range.
	* gimple-range.h (class assume_query): Use ssa_cache.