Bug: error when too long line before ending triple quotes

I have a very simple example where google-java-format errors:

```
class Problem {
static String problematic() {
return """
A too long string directly before the ending triple quote seems to cause a problem with google java formatter""";
}
}
```

When I run the formatter on this file (using `java -jar /path/to/google-java-format-1.17.0-all-deps.jar /path/to/Problem.java`) I get the following error:

```
/path/to/Problem.java:error: Something has gone terribly wrong. We planned to make the below formatting change, but have aborted because it would unexpectedly change the AST.
Please file a bug: https://github.com/google/google-java-format/issues/new

=== Actual: ===

class Problem {

static String problematic() {
return "A too long string directly before the ending triple quote seems to cause a problem\"\n + \" with google java formatter";
}
}
=== Expected: ===

class Problem {

static String problematic() {
return "A too long string directly before the ending triple quote seems to cause a problem with google java formatter";
}
}

```