internal/rosa: tamago toolchain artifact

Currently used by the (wip) bootloader, might not make it into the final OS.

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

internal/rosa/go.go

@@ -160,6 +160,9 @@ rm \
 sed -i \
 	's,/lib/ld-musl-`+linuxArch()+`.so.1,/system/bin/linker,' \
 	cmd/link/internal/`+runtime.GOARCH+`/obj.go
+
+rm \
+	os/root_unix_test.go
 `, go125,
 	)
 }