path solver: Merge path_range_query constructors.

path solver: Merge path_range_query constructors.

There's no need for two constructors, when we can do it all with one
that defaults to the common behavior:

path_range_query (bool resolve = true, gimple_ranger *ranger = NULL);

Tested on x86-64 Linux.

gcc/ChangeLog:

	* gimple-range-path.cc (path_range_query::path_range_query): Merge
	ctors.
	(path_range_query::import_p): Move from header file.
	(path_range_query::~path_range_query): Adjust for combined ctors.
	* gimple-range-path.h: Merge ctors.
	(path_range_query::import_p): Move to .cc file.