[SPARK-14011][CORE][SQL] Enable `LineLength` Java checkstyle rule

## What changes were proposed in this pull request?

[Spark Coding Style Guide](https://cwiki.apache.org/confluence/display/SPARK/Spark+Code+Style+Guide) has 100-character limit on lines, but it's disabled for Java since 11/09/15. This PR enables **LineLength** checkstyle again. To help that, this also introduces **RedundantImport** and **RedundantModifier**, too. The following is the diff on `checkstyle.xml`.

```xml
-        <!-- TODO: 11/09/15 disabled - the lengths are currently > 100 in many places -->
-        <!--
         <module name="LineLength">
             <property name="max" value="100"/>
             <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://"/>
         </module>
-        -->
         <module name="NoLineWrap"/>
         <module name="EmptyBlock">
             <property name="option" value="TEXT"/>
 -167,5 +164,7
         </module>
         <module name="CommentsIndentation"/>
         <module name="UnusedImports"/>
+        <module name="RedundantImport"/>
+        <module name="RedundantModifier"/>
```

## How was this patch tested?

Currently, `lint-java` is disabled in Jenkins. It needs a manual test.
After passing the Jenkins tests, `dev/lint-java` should passes locally.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #11831 from dongjoon-hyun/SPARK-14011.

1 files changed, 2 insertions, 1 deletions

diff --git a/common/unsafe/src/main/java/org/apache/spark/unsafe/bitset/BitSetMethods.java b/common/unsafe/src/main/java/org/apache/spark/unsafe/bitset/BitSetMethods.java
index 7857bf66a7..c8c57381f3 100644
--- a/common/unsafe/src/main/java/org/apache/spark/unsafe/bitset/BitSetMethods.java
+++ b/common/unsafe/src/main/java/org/apache/spark/unsafe/bitset/BitSetMethods.java
@@ -87,7 +87,8 @@ public final class BitSetMethods {
    * To iterate over the true bits in a BitSet, use the following loop:
    * <pre>
    * <code>
-   *  for (long i = bs.nextSetBit(0, sizeInWords); i &gt;= 0; i = bs.nextSetBit(i + 1, sizeInWords)) {
+   *  for (long i = bs.nextSetBit(0, sizeInWords); i &gt;= 0;
+   *    i = bs.nextSetBit(i + 1, sizeInWords)) {
    *    // operate on index i here
    *  }
    * </code>