runtime: expand TestGdbPythonCgo skip to include mips64le

runtime: expand TestGdbPythonCgo skip to include mips64le

The failure mode in #37794 does not match the failure mode described
in #18784. However, since the test is currently skipped on all other
MIPS variants, it may be that they suffer from the same underlying GDB
bug. Ideally one of the Go MIPS maintainers should file an upstream
bug and remove the skip once it is fixed; in the meantime, there is no
point in continuing to let the test fail on just one of the four MIPS
variants.

For #37794

Change-Id: I570f51cc04cbb7ef1ed7efd526e26886af53bfb6
Reviewed-on: https://go-review.googlesource.com/c/go/+/376654
Trust: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>