Improving the coverage and adding more err tests

Signed-off-by: iifawzi <iifawzie@gmail.com>

Author: iifawzi

src/Statements/ExplainStatement.php

@@ -167,10 +167,6 @@ public function parse(Parser $parser, TokensList $list)
                 // assuming that all remaining tokens at state 2, are related to the to-be-explained statement.
                 $idxOfLastParsedToken = $list->count - 1;
                 $subList = new TokensList(array_slice($list->tokens, $list->idx));
-                if ($subList instanceof ParserException) {
-                    $parser->errors[] = $subList;
-                    break;
-                }
 
                 $this->bodyParser = new Parser($subList);
                 if (count($this->bodyParser->errors)) {

tests/Parser/ExplainStatementTest.php

@@ -30,6 +30,7 @@ public function explainProvider(): array
             ['parser/parseExplainErr1'],
             ['parser/parseExplainErr2'],
             ['parser/parseExplainErr3'],
+            ['parser/parseExplainErr4'],
         ];
     }
 }

tests/data/parser/parseExplainErr4.in

@@ -0,0 +1 @@
+EXPLAIN