test/convert5: skip mipsle

test/convert5: skip mipsle

It's broken on 32-bit architectures, and mips (be) has been in the skip
list. mipsle is somehow forgotten, so add it.

Updates #67304

Change-Id: I6d12185c21c37d0524d245e0a7025e30add1fb6b
Reviewed-on: https://go-review.googlesource.com/c/go/+/743740
Reviewed-by: Julian Zhu <jz531210@gmail.com>
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>