SPARK-2787: Make sort-based shuffle write files directly when there's no sorting/aggregation and # partitions is small

As described in https://issues.apache.org/jira/browse/SPARK-2787, right now sort-based shuffle is more expensive than hash-based for map operations that do no partial aggregation or sorting, such as groupByKey. This is because it has to serialize each data item twice (once when spilling to intermediate files, and then again when merging these files object-by-object). This patch adds a code path to just write separate files directly if the # of output partitions is small, and concatenate them at the end to produce a sorted file.

On the unit test side, I added some tests that force or don't force this bypass path to be used, and checked that our tests for other features (e.g. all the operations) cover both cases.

Author: Matei Zaharia <matei@databricks.com>

Closes #1799 from mateiz/SPARK-2787 and squashes the following commits:

88cf26a [Matei Zaharia] Fix rebase
10233af [Matei Zaharia] Review comments
398cb95 [Matei Zaharia] Fix looking up shuffle manager in conf
ca3efd9 [Matei Zaharia] Add docs for shuffle manager properties, and allow short names for them
d0ae3c5 [Matei Zaharia] Fix some comments
90d084f [Matei Zaharia] Add code path to bypass merge-sort in ExternalSorter, and tests
31e5d7c [Matei Zaharia] Move existing logic for writing partitioned files into ExternalSorter
SPARK-2565. Update ShuffleReadMetrics as blocks are fetched

Author: Sandy Ryza <sandy@cloudera.com>

Closes #1507 from sryza/sandy-spark-2565 and squashes the following commits:

74dad41 [Sandy Ryza] SPARK-2565. Update ShuffleReadMetrics as blocks are fetched
[SPARK-2904] Remove non-used local variable in SparkSubmitArguments

Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>

Closes #1834 from sarutak/SPARK-2904 and squashes the following commits:

38e7d45 [Kousuke Saruta] Removed non-used variable in SparkSubmitArguments
[SPARK-2911]: provide rdd.parent[T](j) to obtain jth parent RDD

Author: Erik Erlandson <eerlands@redhat.com>

Closes #1841 from erikerlandson/spark-2911-pr and squashes the following commits:

4699e2f [Erik Erlandson] [SPARK-2911]: provide rdd.parent[T](j) to obtain jth parent RDD
[SPARK-2888] [SQL] Fix addColumnMetadataToConf in HiveTableScan

JIRA: https://issues.apache.org/jira/browse/SPARK-2888

Author: Yin Huai <huai@cse.ohio-state.edu>

Closes #1817 from yhuai/fixAddColumnMetadataToConf and squashes the following commits:

fba728c [Yin Huai] Fix addColumnMetadataToConf.
[SPARK-2908] [SQL] JsonRDD.nullTypeToStringType does not convert all NullType to StringType

JIRA: https://issues.apache.org/jira/browse/SPARK-2908

Author: Yin Huai <huai@cse.ohio-state.edu>

Closes #1840 from yhuai/SPARK-2908 and squashes the following commits:

86e833e [Yin Huai] Update test.
cb11759 [Yin Huai] nullTypeToStringType should check columns with the type of array of structs.
[SPARK-2877] [SQL] MetastoreRelation should use SparkClassLoader when creating the tableDesc

JIRA: https://issues.apache.org/jira/browse/SPARK-2877

Author: Yin Huai <huai@cse.ohio-state.edu>

Closes #1806 from yhuai/SPARK-2877 and squashes the following commits:

4142bcb [Yin Huai] Use Spark's classloader.
[SPARK-2919] [SQL] Basic support for analyze command in HiveQl

The command we will support is
```
ANALYZE TABLE tablename COMPUTE STATISTICS noscan
```
Other cases shown in https://cwiki.apache.org/confluence/display/Hive/StatsDev#StatsDev-ExistingTables will still be treated as Hive native commands.

JIRA: https://issues.apache.org/jira/browse/SPARK-2919

Author: Yin Huai <huai@cse.ohio-state.edu>

Closes #1848 from yhuai/sqlAnalyze and squashes the following commits:

0b79d36 [Yin Huai] Typo and format.
c59d94b [Yin Huai] Support "ANALYZE TABLE tableName COMPUTE STATISTICS noscan".
Fix bug: count the number of quotes instead of detecting presence

A java option of -Dfoo="bar" would fail this previously, because
there are two quotes around bar, but we only detected open quotes
by the presence of the double quote character.
[SPARK-2700] [SQL] Hidden files (such as .impala_insert_staging) should be filtered out by sqlContext.parquetFile

Author: chutium <teng.qiu@gmail.com>

Closes #1691 from chutium/SPARK-2700 and squashes the following commits:

b76ae8c [chutium] [SPARK-2700] [SQL] fixed styling issue
d75a8bd [chutium] [SPARK-2700] [SQL] Hidden files (such as .impala_insert_staging) should be filtered out by sqlContext.parquetFile
[SPARK-1997][MLLIB] update breeze to 0.9

0.9 dependences (this version doesn't depend on scalalogging and I excluded commons-math3 from its transitive dependencies):
~~~
+-org.scalanlp:breeze_2.10:0.9 [S]
  +-com.github.fommil.netlib:core:1.1.2
  +-com.github.rwl:jtransforms:2.4.0
  +-net.sf.opencsv:opencsv:2.3
  +-net.sourceforge.f2j:arpack_combined_all:0.1
  +-org.scalanlp:breeze-macros_2.10:0.3.1 [S]
  | +-org.scalamacros:quasiquotes_2.10:2.0.0 [S]
  |
  +-org.slf4j:slf4j-api:1.7.5
  +-org.spire-math:spire_2.10:0.7.4 [S]
    +-org.scalamacros:quasiquotes_2.10:2.0.0 [S]
    |
    +-org.spire-math:spire-macros_2.10:0.7.4 [S]
      +-org.scalamacros:quasiquotes_2.10:2.0.0 [S]
~~~

Closes #1749

CC: witgo avati

Author: Xiangrui Meng <meng@databricks.com>

Closes #1857 from mengxr/breeze-0.9 and squashes the following commits:

7fc16b6 [Xiangrui Meng] don't know why but exclude a private method for mima
dcc502e [Xiangrui Meng] update breeze to 0.9
Fix bug: escape properly in quote_java_property
Add tests for bash/utils.sh
[SPARK-2897][SPARK-2920]TorrentBroadcast does use the serializer class specified in the spark option "spark.serializer"

Author: GuoQiang Li <witgo@qq.com>

Closes #1836 from witgo/SPARK-2897 and squashes the following commits:

23cdc5b [GuoQiang Li] review commit
ada4fba [GuoQiang Li] TorrentBroadcast does not support broadcast compression
fb91792 [GuoQiang Li] org.apache.spark.broadcast.TorrentBroadcast does use the serializer class specified in the spark option "spark.serializer"
Integrate BASH tests into dev/run-tests + log error properly
Merge branch 'master' of github.com:apache/spark into handle-configs-bash