sql/tests: ignore known issue in TestRandom*

We recently extended sqlsmith to generate DO blocks. This made some
TestRandom* tests fail because - due to a known issue - DO blocks might
not round-trip through Format -> Parse cycle like we generally expect
for all stmts. Until the known issue is fixed, we exempt DO blocks from
this check.

Additionally, this commit adds a common error I saw in the logs to the
set of ignored errors.

Release note: None

Author: yuzefovich

pkg/sql/tests/rsg_test.go

@@ -61,6 +61,17 @@ func verifyFormat(sql string) error {
 		// Cannot serialize a statement list without parsing it.
 		return nil //nolint:returnerrcheck
 	}
+	for _, stmt := range stmts {
+		if _, ok := stmt.AST.(*tree.DoBlock); ok {
+			// We currently don't handle well identifiers with double quotes in
+			// PLpgSQL blocks, so it's likely that this function will fail for
+			// this statement, thus, we skip the check if we see a DO block
+			// (which can only be a top-level AST node).
+			// TODO(#126727): remove this when double-quoted identifiers are
+			// fixed.
+			return nil
+		}
+	}
 	formattedSQL := stmts.StringWithFlags(tree.FmtShowPasswords)
 	formattedStmts, err := parser.Parse(formattedSQL)
 	if err != nil {
@@ -629,6 +640,7 @@ var ignoredErrorPatterns = []string{
 	"AS OF SYSTEM TIME: timestamp before 1970-01-01T00:00:00Z is invalid",
 	"BACKUP for requested time  needs option 'revision_history'",
 	"RESTORE timestamp: supplied backups do not cover requested time",
+	"a partial index that does not contain all the rows needed to execute this query",
 
 	// Numeric conditions
 	"exponent out of range",