[SPARK-27430][SQL] broadcast hint should be respected for broadcast nested loop join

[cloud-fan]

What changes were proposed in this pull request?

A followup of #24164

broadcast hint should be respected for broadcast nested loop join. This PR also refactors the related code a little bit, to save duplicated code.

How was this patch tested?

new tests

[cloud-fan]

cc @maryannxue @gatorsmile

[SparkQA]

Test build #104596 has finished for PR 24376 at commit d69dda2.

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

[SparkQA]

Test build #104595 has finished for PR 24376 at commit 8369227.

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

[maryannxue]

LGTM.

[SparkQA]

Test build #104641 has finished for PR 24376 at commit 9dc9dd1.

• This patch fails due to an unknown error code, -9.
• This patch merges cleanly.
• This patch adds no public classes.

[cloud-fan]

retest this please

[SparkQA]

Test build #104651 has finished for PR 24376 at commit 9dc9dd1.

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

[cloud-fan]

thanks, merging to master!