Remove unused headers from tests

Remove unused headers from tests

	* testsuite/27_io/filesystem/path/decompose/extension.cc: Remove
	unused <vector> header.
	* testsuite/27_io/filesystem/path/query/empty.cc: Likewise.
	* testsuite/27_io/filesystem/path/query/has_extension.cc: Likewise.
	* testsuite/27_io/filesystem/path/query/has_filename.cc: Likewise.
	* testsuite/27_io/filesystem/path/query/has_parent_path.cc: Likewise.
	* testsuite/27_io/filesystem/path/query/has_relative_path.cc:
	Likewise.
	* testsuite/27_io/filesystem/path/query/has_root_directory.cc:
	Likewise.
	* testsuite/27_io/filesystem/path/query/has_root_name.cc: Likewise.
	* testsuite/27_io/filesystem/path/query/has_root_path.cc: Likewise.
	* testsuite/27_io/filesystem/path/query/has_stem.cc: Likewise.
	* testsuite/27_io/filesystem/path/query/is_relative.cc: Likewise.
	* testsuite/experimental/filesystem/path/decompose/extension.cc:
	Likewise.
	* testsuite/experimental/filesystem/path/query/empty.cc: Likewise.
	* testsuite/experimental/filesystem/path/query/has_extension.cc:
	Likewise.
	* testsuite/experimental/filesystem/path/query/has_filename.cc:
	Likewise.
	* testsuite/experimental/filesystem/path/query/has_parent_path.cc:
	Likewise.
	* testsuite/experimental/filesystem/path/query/has_relative_path.cc:
	Likewise.
	* testsuite/experimental/filesystem/path/query/has_root_directory.cc:
	Likewise.
	* testsuite/experimental/filesystem/path/query/has_root_name.cc:
	Likewise.
	* testsuite/experimental/filesystem/path/query/has_root_path.cc:
	Likewise.
	* testsuite/experimental/filesystem/path/query/has_stem.cc: Likewise.
	* testsuite/experimental/filesystem/path/query/is_relative.cc:
	Likewise.

From-SVN: r260256