refix #116

  single line comment in sql will merge next line into before one.

ast/testdata/TestSplitStatement.golden

@@ -31,7 +31,10 @@ where col = 1
 --
 from tb
 where col = 1
-17 
+17 select * from
+-- comment
+tb;
+18 
 -- comment
 0 select * from test\Ghello
 1 select 'hello\Gworld', col from test\Ghello

ast/token.go

@@ -928,6 +928,7 @@ func SplitStatement(buf []byte, delimiter []byte) (string, string, []byte) {
 		if b == '\r' || b == '\n' {
 			if singleLineComment {
 				sql = string(buf[:i])
+				singleLineComment = false
 				if strings.HasPrefix(strings.TrimSpace(sql), "--") ||
 					strings.HasPrefix(strings.TrimSpace(sql), "#") {
 					// just comment, query start with '--', '#'

ast/token_test.go

@@ -146,6 +146,10 @@ where col = 1`),
 --
 from tb
 where col = 1`),
+		[]byte(`select * from
+-- comment
+tb;
+select col from tb where col = 1;`),
 		// https://github.com/XiaoMi/soar/issues/120
 		[]byte(`
 -- comment