gccrs: Remove warning for unused `self` parameter

gccrs: Remove warning for unused `self` parameter

gcc/testsuite/ChangeLog:

	* rust/compile/auto_traits2.rs:
	emove warning for unused `self` parameter
	* rust/compile/derive-debug1.rs:
	emove warning for unused `self` parameter
	* rust/compile/derive_macro1.rs:
	Remove warning for unused `self` parameter
	* rust/compile/format_args_basic_expansion.rs:
	Remove warning for unused `self` parameter
	* rust/compile/format_args_extra_comma.rs:
	Remove warning for unused `self` parameter
	* rust/compile/issue-2043.rs:
	Remove warning for unused `self` parameter
	* rust/compile/issue-2166.rs:
	Remove warning for unused `self` parameter
	* rust/compile/issue-2238.rs:
	Remove warning for unused `self` parameter
	* rust/compile/issue-2907.rs:
	Remove warning for unused `self` parameter
	* rust/compile/min_specialization1.rs:
	Remove warning for unused `self` parameter
	* rust/compile/name_resolution2.rs:
	Remove warning for unused `self` parameter
	* rust/compile/name_resolution4.rs:
	Remove warning for unused `self` parameter
	* rust/compile/torture/generics29.rs:
	Remove warning for unused `self` parameter
	* rust/compile/torture/generics30.rs:
	Remove warning for unused `self` parameter
	* rust/compile/torture/traits3.rs:
	Remove warning for unused `self` parameter
	* rust/compile/torture/traits7.rs:
	Remove warning for unused `self` parameter
	* rust/execute/torture/impl_trait3.rs:
	Remove warning for unused `self` parameter
	* rust/execute/torture/min_specialization2.rs:
	Remove warning for unused `self` parameter
	* rust/execute/torture/trait10.rs:
	Remove warning for unused `self` parameter
	* rust/execute/torture/trait11.rs:
	Remove warning for unused `self` parameter
	* rust/execute/torture/trait12.rs:
	Remove warning for unused `self` parameter
	* rust/execute/torture/trait13.rs:
	Remove warning for unused `self` parameter
	* rust/execute/torture/trait9.rs:
	Remove warning for unused `self` parameter

Signed-off-by: Ryutaro Okada <1015ryu88@gmail.com>