material/form-field(appearance): not matching Material color specs on hover

[NicholasCobbFromGoogle]

What is the expected behavior?

According to the latest version of the Google Material spec, hovering for "fill" inputs should be 1dp/grey-700 and for "outline" inputs 1dp/grey-300.

What is the current behavior?

For elements using mat-form-field with appearance="fill", "standard" or "outline", the hover-state border is 2dp/rgba(0, 0, 0, 0.87). This is significantly darker than the specification color and has the wrong weight.

What are the steps to reproduce?

This current behavior should be readily visible in any mat-form-field that uses any of the 3 aforementioned appearances.

Here is the example usage from the Angular Material site.
https://stackblitz.com/angular/epjajgjbbve?file=app%2Fform-field-appearance-example.ts

Which versions of Angular, Material, OS, TypeScript, browsers are affected?

Angular Material: 7.3.5
Chrome: 72.0.3626.121 (should still be reproducible on others)
OS: Linux (should still be reproducible on others)

"dependencies": {
"@angular/animations": "8.0.0-beta.6",
"@angular/common": "8.0.0-beta.6",
"@angular/compiler": "8.0.0-beta.6",
"@angular/core": "8.0.0-beta.6",
"@angular/elements": "8.0.0-beta.6",
"@angular/forms": "8.0.0-beta.6",
"@angular/platform-browser": "8.0.0-beta.6",
"@webcomponents/custom-elements": "^1.1.0",
"core-js": "^2.6.1",
"rxjs": "^6.4.0",
"systemjs": "0.19.43",
"tsickle": "^0.34.0",
"tslib": "^1.9.3",
"zone.js": "^0.8.29"
},

Is there anything else we should know?

This has already been discussed beforehand with @mmalerba.

[ghost]

This is annoying, any official signal?