pgsql: Rename various "freeze multixact" variables

Rename various "freeze multixact" variables

It seems to make more sense to use "cutoff multixact" terminology
throughout the backend code; "freeze" is associated with replacing of an
Xid with FrozenTransactionId, which is not what we do for MultiXactIds.

Andres Freund
Some adjustments by Álvaro Herrera

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/dd778e9d888454fdd2c25c66fc268ba9844eb125

Modified Files
--------------
src/backend/access/heap/heapam.c | 4 +--
src/backend/access/heap/rewriteheap.c | 12 ++++-----
src/backend/access/transam/multixact.c | 2 +-
src/backend/commands/cluster.c | 31 +++++++++++-----------
src/backend/commands/dbcommands.c | 2 +-
src/backend/commands/vacuum.c | 44 ++++++++++++++++----------------
src/backend/commands/vacuumlazy.c | 12 ++++-----
src/backend/postmaster/autovacuum.c | 9 +++----
src/include/access/rewriteheap.h | 2 +-
src/include/commands/cluster.h | 2 +-
src/include/commands/vacuum.h | 2 +-
11 files changed, 61 insertions(+), 61 deletions(-)