Render single spaces in DROP PRIMARY KEY, RENAME TABLE and indexes

[minleejae]

Purpose

Render DDL with single spaces between words. Today:

• ALTER TABLE t DROP PRIMARY KEY ends with a space, and with a parameter renders DROP PRIMARY KEY CASCADE.
• RENAME TABLE t TO t2 renders RENAME TABLE t TO t2.
• ALTER TABLE t ADD INDEX i (a) renders ADD INDEX i (a).

The SQL still reparses, but the extra spaces differ from the input and from each other.

Current design (As-is)

• The DROP PRIMARY KEY renderer appends a trailing space. The shared tail adds its own space before parameters.
• RenameTableStatement appends " TABLE " and then " " or " IF EXISTS ".
• Index prefixes its keyword and name with a space even when no index type precedes them. An index with only a keyword or a name therefore renders a leading space.

Target design (To-be)

• Separate these words with exactly one space and add no leading or trailing space.
• Rendered SQL is otherwise unchanged. The SQL renderer and StatementDeParser produce the same text.

Validation

• New DeparseWhitespaceTest:
  • Compares toString() and StatementDeParser output exactly for DROP PRIMARY KEY (alone, with CASCADE, and followed by another action), RENAME (with and without TABLE, IF EXISTS, and several tables), ADD INDEX/ADD KEY, and an index inside CREATE TABLE.
  • Checks constructed Index declarations directly.
• Three existing assertions that encoded ADD INDEX now expect a single space.
• Java 17 offline Gradle spotlessApply check: 10,105 tests, 10,080 passed, 25 skipped, zero failures/errors.
• Ran the rendered statements on MySQL 8.4, MySQL 8.0 and MariaDB 11.4 (19 cases), including MariaDB RENAME TABLE IF EXISTS. All succeed in original and rendered form.

Integration validation

Applied #2788, #2789, #2790, #2791 and #2792 together on master (166f0a27):

• Every pair merges without conflicts, and the combined grammar is free of choice conflicts.
• The integrated build passes Java 17 offline Gradle spotlessApply check: 10,150 tests, 10,125 passed, 25 skipped, zero failures/errors.
• With the integrated build, the same server results hold on MySQL 8.4, MySQL 8.0, MariaDB 11.4 and PostgreSQL 18.3:
  • the 95 statement cases of these PRs;
  • the 11 default-mode drop cases;
  • 51 string literal comparisons, including 16 mixed-escape literals that need Lex MySQL backslash escapes consistently in string literals #2790 and Resolve backslash escapes in StringValue.getNotExcapedValue() #2791 together.