Formatter should understand single line if-blocks without curlies

[DartBot]

<img src="https://avatars.githubusercontent.com/u/1731736?v=3" align="left" width="96" height="96"hspace="10"> Issue by tonygentilcore
Originally opened as dart-lang/sdk#23334

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Run the formatter with an 80 col limit on a single line if-block whose condition fits within 80 cols, but predicate does not. For example:
if (foo = "1234567890123456789012345678901234567890") bar = "12345678901234567890";

Notice it formats to:
if (foo = "1234567890123456789012345678901234567890") bar =
    "12345678901234567890";

I'd expect it to produce:
if (foo = "1234567890123456789012345678901234567890")
  bar = "12345678901234567890";

Or better yet, add the curlies as specified by https://www.dartlang.org/articles/style-guide/#do-use-curly-braces-for-all-flow-control-structures , thus producing:
if (foo = "1234567890123456789012345678901234567890") {
  bar = "12345678901234567890";
}

Note that the formatter does the right thing if the curlies are already present.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/444270?v=3" align="left" width="48" height="48"hspace="10"> Comment by seaneagan

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The formatter will not do this for you:

#45
#182

Hopefully the linter will though:

dart-lang/sdk#57151

[DartBot]

<img src="https://avatars.githubusercontent.com/u/4865287?v=3" align="left" width="48" height="48"hspace="10"> Comment by lrhn

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Added Area-Formatter, Triaged labels.

[munificent]

@seaneagen is right.