* [fix][task plugin][task sql] fix parsing error while using variables sometimes parsing exception happened if task sql contains a variable followed by \" or \' .
for example:
input sql: load inpath '/tmp/test_table/dt=${dt}'
into table test_table partition(dt=${dt})
after replace: preparing : load inpath '/tmp/test_table/dt=?
into table test_table partition(dt=?)
Alex Ting