implement the rest of the language features in the self-hosted x86 backend

[andrewrk]

zig/src/target.zig

Lines 597 to 615 in 085cc54

	.error_return_trace => switch (backend) {
	.stage2_llvm => true,
	else => false,
	},
	.is_named_enum_value => switch (backend) {
	.stage2_llvm => true,
	else => false,
	},
	.error_set_has_value => switch (backend) {
	.stage2_llvm, .stage2_wasm => true,
	else => false,
	},
	.field_reordering => switch (backend) {
	.stage2_c, .stage2_llvm => true,
	else => false,
	},
	.safety_checked_instructions => switch (backend) {
	.stage2_llvm => true,
	else => false,

• compiler: include error trace in all functions, implement for x86_64 backend #22572
• is_named_enum_value
• error_set_has_value
• x86_64: enable struct field reordering #22521
• safety_checked_instructions
• self-hosted x86 backend has formatted panics disabled #21529