pgsql: When a row fails a not-null constraint, show row's contents in e

When a row fails a not-null constraint, show row's contents in errdetail.

Simple extension of previous patch for CHECK constraints.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/f225e4bc54df77e766b0edcffacb865648b099a3

Modified Files
--------------
src/backend/executor/execMain.c | 4 +++-
src/test/regress/expected/alter_table.out | 10 ++++++++++
src/test/regress/expected/domain.out | 4 ++++
src/test/regress/expected/inherit.out | 1 +
src/test/regress/expected/insert.out | 1 +
src/test/regress/expected/sequence.out | 1 +
src/test/regress/expected/sequence_1.out | 1 +
src/test/regress/output/constraints.source | 2 ++
8 files changed, 23 insertions(+), 1 deletions(-)