[SPARK-3755][Core] Do not bind port 1 - 1024 to server in spark

Non-root user use port 1- 1024 to start jetty server will get the exception " java.net.SocketException: Permission denied", so not use these ports

Author: scwf <wangfei1@huawei.com>

Closes #2610 from scwf/1-1024 and squashes the following commits:

cb8cc76 [scwf] do not use port 1 - 1024

(cherry picked from commit 6390aae4eacbabfb1c53fb828b824f6a6518beff)
Signed-off-by: Andrew Or <andrewor14@gmail.com>
SPARK-2626 [DOCS] Stop SparkContext in all examples

Call SparkContext.stop() in all examples (and touch up minor nearby code style issues while at it)

Author: Sean Owen <sowen@cloudera.com>

Closes #2575 from srowen/SPARK-2626 and squashes the following commits:

5b2baae [Sean Owen] Call SparkContext.stop() in all examples (and touch up minor nearby code style issues while at it)

Conflicts:
	examples/src/main/python/parquet_inputformat.py