cmd/bench: increase timeout for gopls tests to 60m

The benchmarks are regularly timing out due to slow network and
builder congestion.

Change-Id: Ia2ac5a7c39e07717a0e61a28e86ab223aed2d17a
Reviewed-on: https://go-review.googlesource.com/c/benchmarks/+/503515
Reviewed-by: Michael Pratt <mpratt@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
1 file changed