RFR: 8374342: Remove incorrect @throws NoSuchFileException from FileUtils.java

[eunbin son]

### Summary
Remove incorrect @throws documentation from FileUtils.deleteFileIfExistsWithRetry.

### Description
The method documentation states that no exception is thrown if the file does not exist.
The implementation checks file existence before deletion and does not throw NoSuchFileException in this case.
This change removes the contradictory @throws clause.
No behavior is changed. 

### Bug ID : JDK-8374342
https://bugs.java.com/bugdatabase/view_bug?bug_id=8374342

-------------

Commit messages:
 - 8374342: Remove incorrect @throws NoSuchFileException from FileUtils.java

Changes: https://git.openjdk.org/jdk/pull/28985/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28985&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8374342
  Stats: 2 lines in 1 file changed: 0 ins; 2 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/28985.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28985/head:pull/28985

PR: https://git.openjdk.org/jdk/pull/28985