[SPARK-24754][ML] Minhash integer overflow

[srowen]

What changes were proposed in this pull request?

Use longs in calculating min hash to avoid bias due to int overflow.

How was this patch tested?

Existing tests.

[SparkQA]

Test build #92877 has finished for PR 21750 at commit aed50d7.

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

[SparkQA]

Test build #92942 has finished for PR 21750 at commit edaed32.

• This patch fails Python style tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #92953 has finished for PR 21750 at commit 55f70ee.

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

[srowen]

Merged to master