pgsql: Change the way UESCAPE is lexed, to reduce the size of the flex

Change the way UESCAPE is lexed, to reduce the size of the flex tables.

The error rule used to avoid backtracking with the U&'...' UESCAPE 'x'
syntax bloated the flex tables, so refactor that. This patch makes the error
rule shorter, by introducing a new exclusive flex state that's entered after
parsing U&'...'. This shrinks the postgres binary by about 220kB.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/a5ff502fceadc7c203b0d7a11b45c73f1b421f69

Modified Files
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src/backend/parser/scan.l |   81 ++++++++++++++++++++++++++++++++++----------
1 files changed, 62 insertions(+), 19 deletions(-)