[SPARK-17299] TRIM/LTRIM/RTRIM should not strips characters other than spaces

[techaddict]

What changes were proposed in this pull request?

TRIM/LTRIM/RTRIM should not strips characters other than spaces, we were trimming all chars small than ASCII 0x20(space)

How was this patch tested?

fixed existing tests.

[SparkQA]

Test build #64798 has finished for PR 14924 at commit 58c2a5d.

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

[rxin]

Can you add a unit test for this?

[techaddict]

@rxin Done 👍

[SparkQA]

Test build #64827 has finished for PR 14924 at commit 554f46c.

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

[srowen]

The implementation in stringExpressions.scala generates code that calls trim(), so just double-checking, that's calling UTF8String not String right? Then yeah LGTM

[techaddict]

@srowen yes in stringExpressions the trim is UTF8String.trim().

[SparkQA]

Test build #64856 has finished for PR 14924 at commit 7583070.

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

[srowen]

LGTM. Seems like this should go into 2.0.x as well since it's really a bug fix.

[srowen]

Merged to master/2.0

[srowen]

Merged to master/2.0