pgsql: nbtree: Rename nbtinsert.c variables for consistency.

nbtree: Rename nbtinsert.c variables for consistency.

Stop naming special area/opaque pointer variables 'lpageop' in contexts
where it doesn't make sense. This is a holdover from a time when logic
that performs tasks that are now spread across _bt_insertonpg(),
_bt_findinsertloc(), and _bt_split() was more centralized. 'lpageop'
denotes "left page", which doesn't make sense outside of contexts in
which there isn't also a right page.

Also acquire page flag variables up front within _bt_insertonpg(). This
makes it closer to _bt_split() following refactoring commit bc3087b626d.
This allows the page split and retail insert paths to both make use of
the same variables.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/a034f8b60c6e9afd75f42dc420a76cb9d3875fcb

Modified Files
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src/backend/access/nbtree/nbtinsert.c | 121 +++++++++++++++++-----------------
1 file changed, 62 insertions(+), 59 deletions(-)