Ignore two tests on s390x

[glaubitz]

Ignore two tests on s390x which don't make sense on s390x as they are x86-specific.

[rust-highfive]

r? @nikomatsakis

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[nikic]

@bors r+ rollup

Would be nice to have something like only-x86 to avoid these types of lists.

[bors]

📌 Commit ecdbcad has been approved by nikic

[petrochenkov]

@nikic
We do have only-x86.
Not sure how multiple only directives work though, e.g.

// only-x86
// only-x86_64

From compiletest code it seems like it does the right thing.

[nikic]

Ah, right! Looks like it marks the test as ignored if any of the only lines do not match, so having multiple only lines will never run the test:

rust/src/tools/compiletest/src/header.rs

Lines 112 to 119 in ddab10a

	if config.has_cfg_prefix(ln, "only") {
	props.ignore = match config.parse_cfg_name_directive(ln, "only") {
	ParsedNameDirective::Match => props.ignore,
	ParsedNameDirective::NoMatch => Ignore::Ignore,
	ParsedNameDirective::MatchLldb => props.ignore.no_gdb(),
	ParsedNameDirective::MatchGdb => props.ignore.no_lldb(),
	};
	}