Description:
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It would be better to throw SolrIllegalArgumentException instead of E_ERROR while setting invalid parameters, using SolrParams and its descendents.

Test script:
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$query = new SolrQuery();
$query->setQuery('');
// or 
$params = new SolrModifiableParams();
$params->addParam('',1);

Expected result:
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Fatal error: Uncaught exception 'SolrIllegalArgumentException' with message 'Invalid parameter value'

Actual result:
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Fatal error: SolrQuery::setQuery(): Invalid parameter value