Add fused conv2d and fused prelu activation.

[annxingyuan]

This change is 

[nsthorat]

Reviewed 3 of 3 files at r1.
Reviewable status: complete! 1 of 1 approvals obtained (waiting on @annxingyuan, @nkreeger, and @nsthorat)

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src/nodejs_kernel_backend.ts, line 351 at r1 (raw file):

 activation?: Activation, preluActivationWeights?: Tensor): Tensor4D { let result = this.conv2d(x, filter, convInfo); if (bias) {

bias != null

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src/nodejs_kernel_backend.ts, line 355 at r1 (raw file):

 } if (activation) {

activation != null

[annxingyuan]

Reviewable status: complete! 1 of 1 approvals obtained (waiting on @nkreeger)

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src/nodejs_kernel_backend.ts, line 351 at r1 (raw file):

Previously, nsthorat (Nikhil Thorat) wrote…

bias != null

Done

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src/nodejs_kernel_backend.ts, line 355 at r1 (raw file):

Previously, nsthorat (Nikhil Thorat) wrote…

activation != null

Done