[SPARK-7913][Core]Make AppendOnlyMap use the same growth strategy of OpenHashSet and consistent exception message

[zsxwing]

This is a follow up PR for #6456 to make AppendOnlyMap consistent with OpenHashSet.

/cc @srowen @andrewor14

[srowen]

I suppose this doesn't have the same overflow issue if the max is 2^29, OK. Yes nice to try to make these a little more consistent.

[SparkQA]

Test build #35121 has finished for PR 6879 at commit dd4385b.

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

[SparkQA]

Test build #35123 has finished for PR 6879 at commit 912c0ad.

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

[zsxwing]

retest this please

[SparkQA]

Test build #35124 has finished for PR 6879 at commit 912c0ad.

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