generic: fix several gtest issues

[sgeor255]

Description

This PR fixes several gtest issues on generic vendor:

• NDR.LocalSize[0]==0 assertion was being thrown due to problems with 0-dim input/outputs not handled correctly
• Several unsupported cases were not skipped
• PRELU was missing a check for post-ops in init()
• InnerProduct & RNN tests were not skipped (IP & RNN are not implemented on generic vendor yet)
• There are some examples that are still failing due to unimplemented features which will be fixed in a separate PR
• ~~There are some convolution backward data & deconvolution tests that are still failing which will be fixed in a separate PR (as the issue doesn't seem to be caused by missing skips)~~

[sgeor255]

The failing CI check is in a file not added by this PR.

[sgeor255]

make test disable device_cpu enable device_gpu enable thr_cuda enable arch_rtx

[mgouicem]

make test disable device_cpu enable device_gpu enable thr_generic enable arch_rtx