Add test case for parsing of double opening '(('

Summary:
Parsing of e.g. "a OR ((b AND c) AND d)" currently fails, as for
the opening '((' only one token is created by the lexer.

CCBUG:392620

Test Plan:
```
QDEBUG : AdvancedQueryParserTest::testNestedParentheses(a OR ((b AND c) AND d))   result term [ OR ( : a (QString)) [ AND ( : b (QString)) ( : c (QString)) ] ( : d (QString)) ]
QDEBUG : AdvancedQueryParserTest::testNestedParentheses(a OR ((b AND c) AND d)) expected term [ OR ( : a (QString)) [ AND ( : b (QString)) ( : c (QString)) ( : d (QString)) ] ]
XFAIL  : AdvancedQueryParserTest::testNestedParentheses(a OR ((b AND c) AND d)) Opening '((' parsed incorrectly
```

Reviewers: #baloo, michaelh

Reviewed By: michaelh

Subscribers: #frameworks

Tags: #frameworks, #baloo

Differential Revision: https://phabricator.kde.org/D12007