Emulate the VERSION() function in the SQLite driver (#281)

Emulate the `VERSION()` function in the SQLite driver

This replaces the old implementation from the legacy SQLite translator
that's defined in `WP_SQLite_PDO_User_Defined_Functions` and returns
`5.5`.

Emulating it directly in the driver should also be faster than calling a
PHP function from SQLite.

This function is used in WordPress core and causes outdated database
warning on the Site Health screen.

Author: JanJakes

tests/WP_SQLite_Driver_Tests.php

@@ -11134,4 +11134,9 @@ public function testUpdateErrorsInNonStrictMode(): void {
 			"SQLSTATE[42S22]: Column not found: 1054 Unknown column 'missing_column' in 'field list'"
 		);
 	}
+
+	public function testVersionFunction(): void {
+		$result = $this->engine->query( 'SELECT VERSION()' );
+		$this->assertSame( '8.0.38', $result[0]->{'VERSION()'} );
+	}
 }

wp-includes/sqlite-ast/class-wp-sqlite-driver.php

@@ -3963,6 +3963,15 @@ private function translate_function_call( WP_Parser_Node $node ): string {
 					$found_rows = count( $this->last_result );
 				}
 				return $found_rows;
+			case 'VERSION':
+				$version = (string) $this->mysql_version;
+				$value   = sprintf(
+					'%d.%d.%d',
+					$version[0],
+					substr( $version, 1, 2 ),
+					substr( $version, 3, 2 )
+				);
+				return $this->connection->quote( $value );
 			default:
 				return $this->translate_sequence( $node->get_children() );
 		}