Speed up an export of shortreads from fastq to fasta format

1. Download the file "https://ugene.unipro.ru/svn/ugene/UGENE-NIAID/XmlTests/Tuxedo/_input/niaid_sample/original_files/lymph_aln.fastq"
2. Open it as separate sequences
Expected state: it takes a few minutes, then the file has appeared in sequence view
3. Export it to another file in fasta format using the context menu in project view
Expected state: export operation has taken approximately the same time as the source file opening
Current state: it takes ~ as 2 times as the opening