Fix some test leakage

[eileenmcnaughton]

Overview

Fixes a cause or false fails in unit tests

Before

Doing unit tests which interact with soft credit searching can cause other tests to fail

After

Tests stop leaking

Technical Details

I encountered this as part of the long saga of #14514 - basically there were 3 issues

1. a static class variable that was leaking between test runs - this is just being handled in test tearDown for now as a larger cleanup is needed to properly address
2. the decision as to whether to create a temp table was an in function static variable - which persisted between runs
3. the table itself persisted between runs

Comments

@seamuslee001 FYI with this the soft credit test finally passes!

[civibot]

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[seamuslee001]

looks good to me adding MOP

[seamuslee001]

Jenkins re test this please

[seamuslee001]

Jenkins re test this please