### What changes were proposed in this pull request?
Dataset always does eager analysis now. Thus, `spark.sql.eagerAnalysis` is not used any more. Thus, we need to remove it.
This PR also outputs the plan. Without the fix, the analysis error is like
```
cannot resolve '`k1`' given input columns: [k, v]; line 1 pos 12
```
After the fix, the analysis error becomes:
```
org.apache.spark.sql.AnalysisException: cannot resolve '`k1`' given input columns: [k, v]; line 1 pos 12;
'Project [unresolvedalias(CASE WHEN ('k1 = 2) THEN 22 WHEN ('k1 = 4) THEN 44 ELSE 0 END, None), v#6]
+- SubqueryAlias t
+- Project [_1#2 AS k#5, _2#3 AS v#6]
+- LocalRelation [_1#2, _2#3]
```
### How was this patch tested?
N/A
Author: gatorsmile <gatorsmile@gmail.com>
Closes#15316 from gatorsmile/eagerAnalysis.
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