fix(clippy): resolve warnings surfaced by Rust 1.95 clippy

- src/row_index.rs: drop redundant `.into_iter()` in `zip`
  (useless_conversion)
- src/encoding/integer/rle_v2/delta.rs: rewrite two manual counter
  loops with `.enumerate()` (explicit_counter_loop)
- tests/java_interop.rs: take `&Path` instead of `&PathBuf` in
  `run_meta` / `run_data` / `write_orc` (ptr_arg)

Required to keep CI green on Rust 1.95.0 with `-D warnings`.

Author: youichi-uda

src/encoding/integer/rle_v2/delta.rs

@@ -250,10 +250,8 @@ mod tests {
         .unwrap();
 
         let mut expected = vec![0, 10];
-        let mut i = 1;
-        for d in deltas {
-            expected.push(d + expected[i]);
-            i += 1;
+        for (i, d) in deltas.into_iter().enumerate() {
+            expected.push(d + expected[i + 1]);
         }
         assert_eq!(expected, out);
     }
@@ -279,10 +277,8 @@ mod tests {
         .unwrap();
 
         let mut expected = vec![10_000, 9_999];
-        let mut i = 1;
-        for d in deltas {
-            expected.push(expected[i] - d);
-            i += 1;
+        for (i, d) in deltas.into_iter().enumerate() {
+            expected.push(expected[i + 1] - d);
         }
         assert_eq!(expected, out);
     }

src/row_index.rs

@@ -280,7 +280,7 @@ pub fn parse_stripe_row_indexes(
                 filters.len(),
                 column_id
             );
-            for (entry, bloom) in row_group_index.entries_mut().zip(filters.into_iter()) {
+            for (entry, bloom) in row_group_index.entries_mut().zip(filters) {
                 entry.bloom_filter = Some(bloom);
             }
         }

tests/java_interop.rs

@@ -52,7 +52,7 @@
 
 use std::env;
 use std::io::Write;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use std::process::Command;
 use std::sync::Arc;
 
@@ -94,7 +94,7 @@ fn orc_tools_jar() -> Option<PathBuf> {
 }
 
 /// Run `java -jar <jar> meta <file>` and return stdout+stderr.
-fn run_meta(jar: &PathBuf, orc_path: &PathBuf) -> (bool, String, String) {
+fn run_meta(jar: &Path, orc_path: &Path) -> (bool, String, String) {
     let out = Command::new("java")
         .args([
             "-jar",
@@ -112,7 +112,7 @@ fn run_meta(jar: &PathBuf, orc_path: &PathBuf) -> (bool, String, String) {
 }
 
 /// Run `java -jar <jar> data <file>` and return stdout+stderr.
-fn run_data(jar: &PathBuf, orc_path: &PathBuf) -> (bool, String, String) {
+fn run_data(jar: &Path, orc_path: &Path) -> (bool, String, String) {
     let out = Command::new("java")
         .args([
             "-jar",
@@ -130,7 +130,7 @@ fn run_data(jar: &PathBuf, orc_path: &PathBuf) -> (bool, String, String) {
 }
 
 /// Write `batch` as an ORC file with `codec` to `path`.
-fn write_orc(path: &PathBuf, batch: &RecordBatch, codec: Compression) {
+fn write_orc(path: &Path, batch: &RecordBatch, codec: Compression) {
     let file = std::fs::File::create(path).expect("create orc tempfile");
     let mut writer = ArrowWriterBuilder::new(file, batch.schema())
         .with_compression(codec)