[test] Fix size snapshot including peer dependencies

[eps1lon]

The programmatic API from size-limit does not use the same webpack config as the cli. Therefore peer dependencies were showing up in the snapshot.

By using a custom webpack config we can exclude those and also properly set up aliases instead of using yarn link. This will also save the stats from webpack in a build artifact that can be inspected with e.g. https://chrisbateman.github.io/webpack-visualizer/ or http://webpack.github.io/analyse/

[mui-pr-bot]

@material-ui/core: parsed: -23.82% 😍, gzip: -29.70% 😍
@material-ui/lab: parsed: -38.14% 😍, gzip: -41.73% 😍
@material-ui/styles: parsed: -9.48% 😍, gzip: -10.39% 😍
@material-ui/system: parsed: +7.21% , gzip: +13.92%

Details of bundle changes.

Comparing: ac57a7c...815ab0c

bundle	parsed diff	gzip diff	prev parsed	current parsed	prev gzip	current gzip
@material-ui/core	-23.82%	-29.70%	484,877	369,384	130,093	91,457
@material-ui/core/Paper	-7.70%	-9.87%	83,040	76,647	21,410	19,297
@material-ui/core/Paper.esm	-6.69%	-8.26%	76,728	71,595	20,462	18,771
@material-ui/core/Popper	-79.25%	-77.40%	146,815	30,462	46,826	10,584
@material-ui/core/styles/createMuiTheme	+6.47% 🔺	+10.87% 🔺	16,235	17,286	5,159	5,720
@material-ui/core/useMediaQuery	-73.03%	-69.91%	9,217	2,486	3,503	1,054
@material-ui/lab	-38.14%	-41.73%	295,473	182,793	86,174	50,217
@material-ui/styles	-9.48%	-10.39%	63,755	57,708	18,119	16,237
@material-ui/system	+7.21% 🔺	+13.92% 🔺	15,915	17,062	3,938	4,486
Button	-53.46%	-57.26%	212,888	99,068	61,970	26,484
Modal	-53.27%	-57.61%	211,094	98,649	61,687	26,152
colorManipulator	+41.14% 🔺	+54.77% 🔺	2,290	3,232	838	1,297
docs.landing	+1.91% 🔺	+4.41% 🔺	48,963	49,899	10,275	10,728
docs.main	+0.14% 🔺	+0.22% 🔺	676,139	677,075	205,127	205,583
packages/material-ui/build/umd/material-ui.production.min.js	0.00%	0.00%	320,511	320,511	84,731	84,731

Generated by 🚫 dangerJS against 815ab0c

[eps1lon]

@oliviertassinari This looks about right.

There are some minor increases in e.g. colorManipulator compared to the previous size-limit because size-limit did not include the size of an empty webpack project. However this number was always hard coded and might've been wrong. I think it's fine including the size of an empty project since very small and constant.

[oliviertassinari]

The downside of using named import is the friction it's creating when editing the code. We have to go to the top of the file to add the missing dependencies. What do you think of using a different tradeoff for the server side scripts, where we don't care about the bundle size?

Suggested change

	const { flatten, fromPairs } = require('lodash');
	const lodash = require('lodash');

[eps1lon]

Makes sense to me. Will change