unused import removal leaves extra blank line between package declaration and class Javadoc / declaration

[zhumin8]

When google-java-format removes an unused import statement located between a package declaration and class Javadoc or class declaration, it does not collapse the vertical whitespace in the same formatting pass. As a result, the formatted output contains extra blank lines (two consecutive blank lines instead of one).

Running google-java-format a second time on the output collapses the extra blank line as expected. We observed this in generated code, more context here: googleapis/librarian#7146

Environment

• google-java-format Version: Tested on 1.25.2 through 1.35.0 (including recent builds).
• Operating System: Linux / macOS / Cross-platform

Minimal Reproducible Example

Input Code (TestBug.java)

```java                                                                                                                                                                                 
package com.example;                                                                                                                                                                    

import static io.grpc.MethodDescriptor.generateFullMethodName;

/**
 * Javadoc for class.
 */
public class TestBug {
}

Command Executed

google-java-format TestBug.java

Actual Output (First Pass)

package com.example;


/** Javadoc for class. */
public class TestBug {}

(Notice the two consecutive empty lines between package com.example; and /** Javadoc for class. */.)

Expected Output

package com.example;

/** Javadoc for class. */
public class TestBug {}

Additional Context & Workaround

• Second Pass Result: Executing google-java-format a second time on the first pass output (google-java-format TestBug.java | google-java-format -) produces the correct output with a single blank line.

[shrey070998]

Hi, I’d like to investigate this issue.

I’ll start by adding a regression test for the unused-import case and trace why
vertical whitespace is not normalized after import removal in the same
formatting pass.

[shrey070998]

I noticed that PR #1262 also works on whitespace leftovers from
RemoveUnusedImportsStep and includes related blank-line test failures.

This issue appears to be a narrower idempotency case involving an unused import
between a package declaration and class Javadoc.

Would you prefer a focused regression test and minimal fix for this case in a
separate PR, or should this be handled as part of #1262?