pgsql: Fix length checking for Unicode identifiers containing escapes (

Fix length checking for Unicode identifiers containing escapes (U&"...").

We used the length of the input string, not the de-escaped string, as
the trigger for NAMEDATALEN truncation. AFAICS this would only result
in sometimes printing a phony truncation warning; but it's just luck
that there was no worse problem, since we were violating the API spec
for truncate_identifier(). Per bug #9204 from Joshua Yanovski.

This has been wrong since the Unicode-identifier support was added,
so back-patch to all supported branches.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/44c216330201126d12e466442c667a8e091decd3

Modified Files
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src/backend/parser/scan.l | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)