Line Seperator issue between windows and unix

使用 google-java-format-1.10.0-all-deps.jar 和 MinimalExample.java 示例，分别以 LF 和 CRLF 行尾复现该差异。跟踪 formatter 产生不同换行的原因，然后验证在两个平台上格式化相同源代码时，都能得到一致的输出，且不会多出一个换行符。

When applying GJF, some code is formatted differently between Unix-style line seperators (LF) and Windows-style line seperators (CRLF). With windows-style an extra linebreak is added, caused by the char difference between LF (\n) and CRLF (\r\n).

I changed the line-separator-style with Intellij (File>File Properties> Line Separators, while having the file opened) and got the following outputs:

Executing java -jar google-java-format-1.10.0-all-deps.jar MinimalExample.java when the file is formatted with Unix line endings:

import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

import feign.FeignException;

public class MinimalExample {
  void googleJavaFormatWindowsFail() {

    FeignException feignException = mock(FeignException.class);
    when(feignException.contentUTF8()).thenReturn("""
    {
      "errorCode" : 420
    }
    """);
  }
}

Executing java -jar google-java-format-1.10.0-all-deps.jar MinimalExample.java when the file is formatted with Windows line endings:

import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

import feign.FeignException;

public class MinimalExample {
  void googleJavaFormatWindowsFail() {

    FeignException feignException = mock(FeignException.class);
    when(feignException.contentUTF8())
        .thenReturn("""
    {
      "errorCode" : 420
    }
    """);
  }
}

If two chars are added, Unix-style generates the same line-break:

import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

import feign.FeignException;

public class MinimalExample {
  void googleJavaFormatWindowsFail() {

    FeignException feignException = mock(FeignException.class);
    when(feignException.contentUTF8())
        .thenReturn("""
    {
      "errorCode" : 42069
    }
    """);
  }
}

Done on GJF 1.10.0, 1,9 and 1.8 with Java 15.0.2
Windows 10 10.0
IntelliJ IDEA 2021.1.1 (Community Edition)