lib: switch to object spread where possible

[BridgeAR]

Use the object spread notation instead of using Object.assign.
It is not only easier to read it is also faster as of V8 6.8.

Benchmark with 11.4:

// node benchmark/es/spread-assign.js 
es/spread-assign.js n=1000000 count=5 method="spread": 36,495,416.66835458
es/spread-assign.js n=1000000 count=10 method="spread": 31,889,730.923060697
es/spread-assign.js n=1000000 count=20 method="spread": 151,930.52448171392
es/spread-assign.js n=1000000 count=5 method="assign": 9,476,496.804852217
es/spread-assign.js n=1000000 count=10 method="assign": 4,704,920.0252048215
es/spread-assign.js n=1000000 count=20 method="assign": 123,309.56193177585
es/spread-assign.js n=1000000 count=5 method="_extend": 5,076,862.324845331
es/spread-assign.js n=1000000 count=10 method="_extend": 2,359,288.3170930305
es/spread-assign.js n=1000000 count=20 method="_extend": 382,746.2281006062

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

[nodejs-github-bot]

@BridgeAR build started: https://ci.nodejs.org/blue/organizations/jenkins/node-test-pull-request-lite-pipeline/detail/node-test-pull-request-lite-pipeline/1988/pipeline

[BridgeAR]

CI https://ci.nodejs.org/job/node-test-pull-request/19639/ ✔️

found a point we should address

[devsnek]

i realize this isn't directly related but it would be good to avoid assigning to the argument.

[BridgeAR]

We do that pretty often everywhere throughout the code?

[devsnek]

could be a separate pr i guess... i just figured as long as you're modifying a bunch of these you could change the argument name. non blocking.

[BridgeAR]

Landed in 4b7a530 🎉