[SPARK-22822][TEST] Basic tests for WindowFrameCoercion and DecimalPrecision

## What changes were proposed in this pull request?

Test Coverage for `WindowFrameCoercion` and `DecimalPrecision`, this is a Sub-tasks for [SPARK-22722](https://issues.apache.org/jira/browse/SPARK-22722).

## How was this patch tested?

N/A

Author: Yuming Wang <[email protected]>

Closes #20008 from wangyum/SPARK-22822.

Author: wangyum

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/windowExpressions.scala

@@ -251,8 +251,8 @@ case class SpecifiedWindowFrame(
       TypeCheckFailure(s"Window frame $location bound '$e' is not a literal.")
     case e: Expression if !frameType.inputType.acceptsType(e.dataType) =>
       TypeCheckFailure(
-        s"The data type of the $location bound '${e.dataType} does not match " +
-          s"the expected data type '${frameType.inputType}'.")
+        s"The data type of the $location bound '${e.dataType}' does not match " +
+          s"the expected data type '${frameType.inputType.simpleString}'.")
     case _ => TypeCheckSuccess
   }