common: postops: add post-ops support for binary select op

[avmanerikar]

Description

The PR adds updates post-ops implementations so that they support binary select operation as a post-op:

$dst[i] = cond[i]\quad?\quad src_0[i] \quad:\quad src_1[i]$

The updates account for the third conditional input that the select op requires for computation.

Implements MFDNN-12883.

This also introduces a new benchdnn format for providing arguments to multiple src tensors for a single post-op:

--attr-post-ops=select:DT[.S1_MASK_INPUT[.S1_TAG]][:S2_MASK_INPUT[.S2_TAG]]

Testcase:

./benchdnn --matmul --attr-post-ops=select:f32.per_tensor.ab:per_tensor.ab 5x10:10x5

(Currently, there is no broadcasting support for the conditional src2 tensor. The data type, mask policy and tag for the src2 tensor are fixed as s8, common and any respectively).

[ranukund]

Minor comments suggested, please incorporate as you see fit, thanks!

[avmanerikar]

make test
set test_scope=NIGHTLY
disable test_device_gpu

[avmanerikar]

make test
set test_scope=NIGHTLY
disable test_device_gpu

[dzarukin]

One last comment to address. I'm fine with the rest.

[avmanerikar]

make test
set test_scope=NIGHTLY
disable test_device_gpu