HADOOP-17450. Add Public IOStatistics API.

[steveloughran]

This patch adds to hadoop-common the IOStatistics API
to query IO object instances (filesystems, streams, remote iterators)
for statistics on their I/O Usage: operation count and min/max/mean
durations.

Contributed by Steve Loughran.

[steveloughran]

This is the hadoop-common part of #2553, which @bgaborg has already approved. I'm just pushing this bit of the patch through yetus before the final merge, and will follow with the MR and hadoop-aws bits.

@mehakmeet : once this is in you'll be able to sync your abfs code up

[steveloughran]

All deprecation warnings will go away. Style and javadocs will be corrected

./hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/impl/FunctionsRaisingIOE.java:41:   * @deprecated use {@link org.apache.hadoop.util.functional.FunctionRaisingIOE}: Line is longer than 80 characters (found 81). [LineLength]
./hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/impl/FunctionsRaisingIOE.java:54:   * @deprecated use {@link org.apache.hadoop.util.functional.BiFunctionRaisingIOE}: Line is longer than 80 characters (found 83). [LineLength]
./hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/impl/FunctionsRaisingIOE.java:65:   * @deprecated use {@link org.apache.hadoop.util.functional.CallableRaisingIOE}: Line is longer than 80 characters (found 81). [LineLength]
./hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/statistics/impl/IOStatisticsBinding.java:450:      DurationTracker tracker = createTracker(factory, statistic);: 'method def' child has incorrect indentation level 6, expected level should be 4. [Indentation]
./hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/statistics/impl/IOStatisticsBinding.java:451:      try {: 'try' has incorrect indentation level 6, expected level should be 4. [Indentation]
./hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/statistics/impl/IOStatisticsBinding.java:453:        input.apply();: 'try' child has incorrect indentation level 8, expected level should be 6. [Indentation]
./hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/statistics/impl/IOStatisticsBinding.java:454:      } catch (IOException | RuntimeException e) {: 'try rcurly' has incorrect indentation level 6, expected level should be 4. [Indentation]
./hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/statistics/impl/IOStatisticsBinding.java:456:        tracker.failed();: 'catch' child has incorrect indentation level 8, expected level should be 6. [Indentation]
./hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/statistics/impl/IOStatisticsBinding.java:458:        throw e;: 'catch' child has incorrect indentation level 8, expected level should be 6. [Indentation]
./hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/statistics/impl/IOStatisticsBinding.java:459:      } finally {: 'catch rcurly' has incorrect indentation level 6, expected level should be 4. [Indentation]
./hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/statistics/impl/IOStatisticsBinding.java:463:        tracker.close();: 'finally' child has incorrect indentation level 8, expected level should be 6. [Indentation]
./hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/statistics/impl/IOStatisticsBinding.java:464:      }: 'finally rcurly' has incorrect indentation level 6, expected level should be 4. [Indentation]
./hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/statistics/package-info.java:28: * {@link org.apache.hadoop.fs.statistics.IOStatisticsSource#getIOStatistics()} .: Line is longer than 80 characters (found 81). [LineLength]
./hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/contract/AbstractContractStreamIOStatisticsTest.java:77:  /**: First sentence should end with a period. [JavadocStyle]

[steveloughran]

lots of javadoc complaints about <p></p> constructs; I'd been using them because the rendered javadocs weren't as well split up as the unformatted ones in the text. But if javadoc complains that much -blank lines it is.

[steveloughran]

This is an out of memory error. as I only changed javadocs since the last successful build, I'm going to do the build and javadoc audit locally, and if good: finish off that merge into trunk only.

Then I'll followup with the later changes, again, trunk, until I'm happy to do the CP into branch-3.3