Text block formatting bug in 1.25.1

[protocol7]

Similar to #1195, we're seeing gjf 1.25.1 failing on some specific text blocks:

public interface Foo {

  private static String foo =
      """
       foo\
       bar """;
}

Note the extra space at the end of the text block.

Fails with:

Foo.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: ===

public interface Foo {
    private static String foo = "foobar ";
}
=== Expected: ===

public interface Foo {
    private static String foo = "foobar";
}