Mistake check of yield expression in yield sentence.

[Shylock-Hg]

a = go from 'Tim Duncan' over *; yield $a;
a = go from 'Tim Duncan' over *; yield $a[1][1];

In yield validator, mistake check the evaluable of expression of yield column.

[Shylock-Hg]

@CPWstatic @yixinglu @laura-ding @Aiee @jievince vesoft-inc/nebula-graph#764 will analysis the lifetime of variable by the inputVars of plan node, so we must set the all variable used by one plan node to its inputVars, Or

1. Maybe get empty result for the variable generated by plan node output;
2. Variable keep alive until the query finish for the variable manually generated when validating/planning.

[Shylock-Hg]

This only crash in debug mode, get null in release.

[Shylock-Hg]

Solved in #3211