fix(select): exception when initialized with large amount of options

[crisbeto]

Fixes an error being thrown by mat-select when it is initialized with a large amount of pre-selected options. The issue comes from the fact that we add a change listener right before the initial values are assigned rather than afterwards.

Fixes #12504.

[josephperrott]

LGTM

[Neonides]

When can you expect to deploy of this fix?

[dydome]

Any update?

[ngbot]

Hi @crisbeto! This PR has merge conflicts due to recent upstream merges.
Please help to unblock it by resolving these conflicts. Thanks!

[osipenkom]

Any updates?

[crisbeto]

I'm bumping this to a P2 since we keep getting reports about it.

[crisbeto]

Looks like I rebased this while there were build errors in master. It should be rebased once #16928 gets in.

[ogix]

Any reason not to merge it now? Thanks.
Btw in my case I have a button that selects all the options (~500) in mat-select. After I deselect one of them I get this error. Will this PR fix this case as well?

[andrewseguin]

We are seeing internal failures that seem to be related to using a formControl with preset values. Here's a case that fails due to the trigger not showing the current selected values: https://stackblitz.com/angular/bqeaknagrjy?file=src%2Fapp%2Fselect-reactive-form-example.ts

See this PR for an associated failing test: crisbeto#12

[crisbeto]

I think the underlying issue was fixed in a better way by #17071 a while ago. I tried running the attached unit test against master and it passes without any of these changes. I'll close the PR for now and we can reconsider it if it shows up again.

[andrewseguin]

Awesome!

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