Fix texPageCommitment alignment test

Fix texPageCommitment alignment test

In verifyInvalidValueErrors, the test wants to validate that
texPageCommitment returns a GL_INVALID_VALUE error when the page
depth offset is not a multiple of pageSizeZ.
However if pageSizeZ equals 1, any z offset will be a multiple of
pageSizeZ and the test should not return an error.

Logic is added to make sure there's really an alignment error

Affects:

KHR-GL45.sparse_texture_tests.*

Components: OpenGL

VK-GL-CTS issue: 438

Change-Id: If7a00dee071c1dafabbda608f7cdbb14d1eb56b3