Relax precision for matrix precision tests

Relax precision for matrix precision tests

The Vulkan spec does not specify the precision for inverse and
determinant built in functions, however newly added tests effecitively
adds a precision requirement for them.

The precision required in these tests is too high for some valid
implementations of these builtin functions.

Relax the precision required in the tests to allow valid
implementations to pass.

Affects:
dEQP-VK.glsl.builtin.precision*.determinant.*
dEQP-VK.glsl.builtin.precision*.inverse.*

Compontents: vulkan

VK-GL-CTS issue: 3182

Change-Id: Ib4c5b9d04578732456b8f981bc82a2c86ad877fa