Add clear session button to Request panel #684

Job	Run time
cs-stan / Coding Standard & Static Analysis	40s
testsuite / testsuite-linux (8.4, mysql, highest, false)	44s
testsuite / testsuite-linux (8.2, pgsql, highest, false)	40s
testsuite / testsuite-linux (8.2, mysql, highest, false)	52s
testsuite / testsuite-linux (8.3, sqlite, highest, false)	35s
testsuite / testsuite-linux (8.5, sqlite, highest, false)	28s
testsuite / testsuite-linux (8.2, sqlite, lowest, false)	32s
	4m 31s

Provide feedback