variance_test: Use static arrays for test params
variance_test: Use static arrays for test params

fixes compiler warnings in MSVC related to decorated name truncation

Change-Id: I614e2466651d2f90983ba34ba560d093754c1028

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom