internal/pkg: exclusive artifacts

This alleviates scheduler overhead when curing many artifacts.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/llvm.go

@@ -197,6 +197,8 @@ cp -r /system/include /usr/include && rm -rf /system/include
 			"ROSA_LLVM_RUNTIMES=" + strings.Join(runtimes, ";"),
 		}, attr.env),
 		ScriptEarly: scriptEarly, Script: script + attr.script,
+
+		Exclusive: true,
 	})
 }