Unify dictionary queries on plain select_value(s) with bind variables

[yahonda]

Summary

Extends the bind-variable pattern introduced in #2629 to the remaining all_* / user_* dictionary queries that were still routing through the select_values_forcing_binds / select_value_forcing_binds helpers. After this PR every dictionary query in OracleEnhancedAdapter calls plain select_values(sql, name, binds) / select_value(sql, name, binds) with a :placeholder raw SQL and an explicit binds array — one consistent shape across the file.

As a result, the two helpers select_values_forcing_binds and select_value_forcing_binds no longer have any callers and are removed.

Method	Helper used before	Now
identity_primary_key?	select_values_forcing_binds	select_values
trigger_backed_primary_key?	select_values_forcing_binds	select_values
pk_and_sequence_for (×2)	select_values_forcing_binds	select_values
primary_keys	select_values_forcing_binds	select_values
temporary_table?	select_value_forcing_binds	select_value
(helper definitions, private)	—	(deleted)

Diff: +6 / -22 lines, 1 file.

Why the unification is safe now

The _forcing_binds helpers were added in #2125 (2021) to make dictionary queries use bind variables even inside an unprepared_statement do ... end block, by temporarily removing the connection from prepared_statements_disabled_cache so AR's visitor wouldn't inline the binds.

Two recent changes made that mechanism unnecessary:

1. Bind literals in dictionary queries #2629 finished converting the remaining literal-interpolated dictionary queries to raw SQL with :placeholder markers and explicit binds arrays. AR's visitor isn't involved on the raw-SQL-with-binds path, so there is nothing to inline — the prepared_statements_disabled_cache trick had nothing to defend against on that path.
2. Honor prepared_statements: false in perform_query and _exec_insert #2651 made OracleEnhanced::DatabaseStatements#perform_query honor prepared_statements? directly. Inside an unprepared_statement block, dictionary queries now prepare-bind-exec-close one-shot instead of caching the cursor in @statements, but bind values still flow to the server. SQL-text matching keeps the shared cursor reusable in the database's shared pool — the original server-side cursor-sharing goal of Usage of bind variables for volatile filter conditions (3) #2125 is preserved without the helper.

The helpers were defined under private and were not part of the documented adapter API.

Test plan

• CI green (default prepared_statements: true workflow)
• Daily master test_prepared_statements_false workflow green after merge
• Local — full suite passes in both modes (verified):
  • prepared_statements: true → 613 examples, 0 failures, 7 pending
  • prepared_statements: false → 613 examples, 0 failures, 8 pending

Related

• Builds on Bind literals in dictionary queries #2629 (dictionary queries to binds), Honor prepared_statements: false in perform_query and _exec_insert #2651 (prepared_statements? in perform_query), Respect the database's CURSOR_SHARING setting by default #2626 (respect DB's cursor_sharing).
• Original helper PR: Usage of bind variables for volatile filter conditions (3) #2125