pgsql: Cleanup for pull-up-isReset patch.

Cleanup for pull-up-isReset patch.

Clear isReset before, not after, calling the context-specific alloc method,
so as to preserve the option to do a tail call in MemoryContextAlloc
(and also so this code isn't assuming that a failed alloc call won't have
changed the context's state before failing). Fix missed direct invocation
of reset method. Reformat a comment.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/b23aeb6519651146cf35b2b91d24596f37b40794

Modified Files
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src/backend/utils/mmgr/aset.c | 10 +++++-----
src/backend/utils/mmgr/mcxt.c | 13 +++++++------
2 files changed, 12 insertions(+), 11 deletions(-)