Merged PRs

dolt

3860: bats tests for reading privs.json and converting
tests for: #3859
companion pr: dolthub/go-mysql-server#1124

1124: still read JSON privilege files, but write flatbuffer format
fix for: #3859
tests are in dolt pr
companion pr: #3860
1120: Support where clause for show variables
Where clause is supported only for variable_name column of result table of show variables query.
Fixes #3834
1117: Add foreign key tests where the parent table has inverted primary keys
1116: Add tests for unique key violations and fix engine to pass them
1111: Bug fixes for AlterPK and column defaults
Operations that modify a table's schema were not consistently resolving column default values:
- AlterPK was missed in resolve column default switch cases, and also wasn't considering its expressions when checking for resolution.
- AlterDefaultSet was resolving the wrong schema (its output schema, OkResultSchema, instead of the target schema).
  While I was in there, I cleaned up the code to more consistently use the sql.TargetSchema interface and combined some copy/pasted switch cases.
  Updated existing tests to use column default values and verified they caught both of these failures. Have already run Dolt engine tests and verified they pass correctly.
  Fixes: #3788

3853: Calling SELECT DOLT_BRANCH('-d', '<branch-name>') results in [HY000][1105] attempted to delete a branch that is not fully merged into its parent; use -f to force
3815: Branch deletes (and maybe other things) don't replicate
3788: Panic when altering the PK on a table with column defaults
3834: Show Variables Where Is An Unsupported Feature