tester: Fix tester.Result by removing conversion
tester: Fix tester.Result by removing conversion

The tester.Result#String function was unnecessarily converting the
tester.Result#Duration field into microseconds. This made the reported
latency off by 3-orders of magnitude. This change was only tested
manually because asserting on an expected duration is going to be
flaky.

Fixes #1432

Signed-off-by: Torin Sandall <933af5bec0bc58056526d55ca6c7b45fcf14cc48@gmail.com>

tsandall/opa,open-policy-agent/opa,open-policy-agent/opa,tsandall/opa,open-policy-agent/opa,tsandall/opa,tsandall/opa,tsandall/opa,tsandall/opa,open-policy-agent/opa,open-policy-agent/opa,open-policy-agent/opa