Remove no-op PlaceHolderVars

Applying: Fixing test cases
Using index info to reconstruct a base tree...
M	contrib/postgres_fdw/expected/postgres_fdw.out
M	contrib/postgres_fdw/sql/postgres_fdw.sql
M	src/test/regress/expected/groupingsets.out
M	src/test/regress/expected/join.out
M	src/test/regress/expected/memoize.out
M	src/test/regress/expected/partition_join.out
M	src/test/regress/sql/join.sql
M	src/test/regress/sql/memoize.sql
M	src/test/regress/sql/partition_join.sql
Falling back to patching base and 3-way merge...
Auto-merging src/test/regress/sql/partition_join.sql
Auto-merging src/test/regress/sql/memoize.sql
Auto-merging src/test/regress/sql/join.sql
Auto-merging src/test/regress/expected/partition_join.out
Auto-merging src/test/regress/expected/memoize.out
Auto-merging src/test/regress/expected/join.out
CONFLICT (content): Merge conflict in src/test/regress/expected/join.out
Auto-merging src/test/regress/expected/groupingsets.out
Auto-merging contrib/postgres_fdw/sql/postgres_fdw.sql
Auto-merging contrib/postgres_fdw/expected/postgres_fdw.out
Patch failed at 0001 Fixing test cases

error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config advice.mergeConflict false"