WebGPU performance regression

Steps to reproduce:

1. Build a project in Development Mode
2. In the Chrome DevTools, select Source and select the framework.js file
3. Search for wgpuLinkParentAndChild.

Actual results: 
wgpuLinkParentAndChild has the code 
parent.derivedObjects = {};
which is the source of the performance issue in Chrome.
Expected results: 

wgpuLinkParentAndChild has the code 
parent.derivedObjects = new Map();

Reproducible with versions: 
6000.0.59f

Not reproducible with versions: 
6000.0.27f.

Can’t test with versions: 

Tested on (OS): 

Notes:

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