colexec: short-circuit hash join when build side is empty

[yuzefovich]

Previously, we would always fully consume both sides of the join, even
when the build (right) side is empty. We can, however, short-circuit in
such case for INNER, RIGHT OUTER, and LEFT SEMI joins and skip probing
phase altogether in such scenarios. For example, this helps query 93 of
TPC-DS benchmark with scale factor 1.

Release note: None

[cockroach-teamcity]

This change is 

[yuzefovich]

I noticed this in the output of tpcdsvec:

09:11:42 test.go:190: test status: [q93] took about 3.69s to run on both configs
09:11:42 test.go:190: test status: WARNING: suboptimal plan when stats are present
no stats: 0.13s	with stats: 3.69s

so I got curious what's going on. Took a look at vectorize=off vs vectorize=on and the former was 12ms whereas the latter was 3s, and then I noticed this inefficiency. Explain analyze for vec=off and for vec=on.

[blathers-crl]

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[blathers-crl]

❌ The GitHub CI (Cockroach) build has failed on 4c860fd2.

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[asubiotto]

Reviewed 2 of 2 files at r1.
Reviewable status: complete! 1 of 0 LGTMs obtained

[yuzefovich]

TFTR!

bors r+

[craig]

Merge conflict (retrying...)

[craig]

Build failed (retrying...)

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[craig]

Build succeeded

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