[SPARK-12058][STREAMING][KINESIS][TESTS] fix Kinesis python tests

[brkyvz]

Python tests require access to the KinesisTestUtils file. When this file exists under src/test, python can't access it, since it is not available in the assembly jar.

However, if we move KinesisTestUtils to src/main, we need to add the KinesisProducerLibrary as a dependency. In order to avoid this, I moved KinesisTestUtils to src/main, and extended it with ExtendedKinesisTestUtils which is under src/test that adds support for the KPL.

cc @zsxwing @tdas

[SparkQA]

Test build #46910 has finished for PR 10050 at commit 2e27264.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[zsxwing]

@brkyvz could you enable KinesisStreamTests in this PR? I just disabled it to unblock other PR.

[brkyvz]

jenkins retest this please

[SparkQA]

Test build #46926 has finished for PR 10050 at commit 42d163c.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[tdas]

jenkins, test this please

[brkyvz]

jenkins test this please

[SparkQA]

Test build #47091 has finished for PR 10050 at commit 9c208d7.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #47090 has finished for PR 10050 at commit 9c208d7.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[tdas]

Lets name it KinesisDataGenerator, to avoid confusion with "producer" in KPL.
KinesisProducer --> KinesisDataGenerator
KinesisClientProducer --> SimpleDataGenerator
KinesisProducerLibraryProducer --> KPLDataGenerator

[SparkQA]

Test build #47102 has finished for PR 10050 at commit 0192d2d.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #2169 has finished for PR 10050 at commit 0192d2d.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #2170 has finished for PR 10050 at commit 0192d2d.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[tdas]

LGTM. Merging this to master and 1.6. Thanks!