Relax TestGpuNnapi accuracy check with a tolerance.

Prior to this CL, TestGpuNnapi expects the actual result to match with
the expected value exactly. This CL defines a set of tolerance for the
accuracy check in TestGpuNnapi, and expects the difference between the
actual and expected value to be within the tolerance.

Bug: 196334691
Test: NNT_static
Change-Id: I08cb83e8d1c4f5df72f7f324b237871f77c5265f
Merged-In: I08cb83e8d1c4f5df72f7f324b237871f77c5265f
(cherry picked from commit 8d05fe4eb1cd516569b29363c05cd78230faff98)
1 file changed