[SPARK-17276][Core][Test] Stop env params output on Jenkins job page

[keypointt]

https://issues.apache.org/jira/browse/SPARK-17276

What changes were proposed in this pull request?

When trying to find error msg in a failed Jenkins build job, I'm annoyed by the huge env output.
The env parameter output should be muted.

How was this patch tested?

Tested manually on local laptop.

[srowen]

LGTM though SQLQuerySuite has exactly the same construction and could use a similar treatment.

[keypointt]

sure I'll change SQLQuerySuite too

[SparkQA]

Test build #64521 has finished for PR 14848 at commit 247e852.

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

[SparkQA]

Test build #64535 has finished for PR 14848 at commit b631901.

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

[SparkQA]

Test build #64541 has finished for PR 14848 at commit adf3d5b.

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

[srowen]

Merged to master