Add aarch64_be-unknown-hermit target

Signed-off-by: Jens Reidel <adrian@travitia.xyz>

src/bootstrap/src/core/sanity.rs

@@ -35,6 +35,7 @@ pub struct Finder {
 const STAGE0_MISSING_TARGETS: &[&str] = &[
     "armv7a-vex-v5",
     // just a dummy comment so the list doesn't get onelined
+    "aarch64_be-unknown-hermit",
     "aarch64_be-unknown-none-softfloat",
 ];