database/sql: remove duplicate validation

Since https://golang.org/cl/38533, this validation is performed in
driverArgs.

Change-Id: I13a3ca46a1aa3197370de1095fb46ab83ea4628c
Reviewed-on: https://go-review.googlesource.com/91115Reviewed-by: Daniel Theophanes <kardianos@gmail.com>
Run-TryBot: Daniel Theophanes <kardianos@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/database/sql/sql.go

@@ -2262,13 +2262,6 @@ func resultFromStatement(ctx context.Context, ci driver.Conn, ds *driverStmt, ar
 		return nil, err
 	}
 
-	// -1 means the driver doesn't know how to count the number of
-	// placeholders, so we won't sanity check input here and instead let the
-	// driver deal with errors.
-	if want := ds.si.NumInput(); want >= 0 && want != len(dargs) {
-		return nil, fmt.Errorf("sql: statement expects %d inputs; got %d", want, len(dargs))
-	}
-
 	resi, err := ctxDriverStmtExec(ctx, ds.si, dargs)
 	if err != nil {
 		return nil, err
@@ -2440,13 +2433,6 @@ func rowsiFromStatement(ctx context.Context, ci driver.Conn, ds *driverStmt, arg
 		return nil, err
 	}
 
-	// -1 means the driver doesn't know how to count the number of
-	// placeholders, so we won't sanity check input here and instead let the
-	// driver deal with errors.
-	if want := ds.si.NumInput(); want >= 0 && want != len(dargs) {
-		return nil, fmt.Errorf("sql: statement expects %d inputs; got %d", want, len(dargs))
-	}
-
 	rowsi, err := ctxDriverStmtQuery(ctx, ds.si, dargs)
 	if err != nil {
 		return nil, err