Restore reader_count in case of failure in rwlock_rdlock_impl

[shanhe72101]

What problem does this PR solve?

Issue Number: Fix #3051

Problem Summary:

What is changed and the side effects?

Changed:

Side effects:

• Performance effects:

• Breaking backward compatibility:

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Check List:

• Please make sure your changes are compilable.
• When providing us with a new feature, it is best to add related tests.
• Please follow Contributor Covenant Code of Conduct.

[wwbmmm]

LGTM

[shanhe72101]

Please add a UT.

done

[shanhe72101]

@chenBright please review,thank you

[shanhe72101]

@chenBright

1. reader_sema should also be restored.
2. The same problem exists with wlock.

In case of timeout, reader_sema will not be modified and does not require restoration. The same applies to rwlock->writer_sema. Perhaps I haven't uncovered the truth. Please point out the specific errors, thank you

[chenBright]

bthread1                                                  bthread2
bthread_sem_timedwait
                                                          rwlock->reader_count->fetch_add(RWLockMaxReaders);
                                                          bthread_sem_post_n
                                                          bthread_mutex_unlock
rwlock->reader_count->fetch_add

In this case, reader_sema has been posted. Subsequently, there may be a problem where the write lock and read lock enter the critical section at the same time.