Border color behaviour breaks in Android in 0.51

[AndrewIngram]

I've been using the old trick from CSS days to draw triangles with React Native, eg:

<View style={{
  width: 64,
  height: 64,
  borderWidth: 32,
  borderColor: 'red',
  borderTopColor: 'transparent',
  borderLeftColor: 'transparent',
 }} />

Expo Snack reproduction here: https://snack.expo.io/Skyt2nPzG (Switch between SDK 24 and 23 to toggle between React Native 0.51 and 0.50)

In React Native 0.50 and earlier, this correctly renders like this:

In React Native 0.51 it renders like this:

Explicitly defining border colors for all sides seems to be a workaround:

<View style={{
  width: 64,
  height: 64,
  borderWidth: 32,
  borderRightColor: 'red',
  borderBottomColor: 'red',
  borderTopColor: 'transparent',
  borderLeftColor: 'transparent',
 }} />

iOS behaves as expected in all versions.

[react-native-bot]

@facebook-github-bot no-template

[facebook-github-bot]

Hey @AndrewIngram, thanks for posting this! It looks like your issue is missing some required information. Can you please add all the details specified in the Issue Template? This is necessary for people to be able to understand and reproduce your issue. I am going to close this, but please feel free to open a new issue with the additional information provided. Thanks!

_{How to Contribute • What to Expect from Maintainers}

[shergin]

cc @RSNara

[stale]

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[react-native-bot]

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