Broker throws RuntimeException on GroupBy metric with filter applied on NaN values

### Affected Version
0.19

The Druid version where the problem was encountered.
0.19

### Description

Simple groupby query like

```
SELECT sum(someMetric), someDimension from someDatasource
WHERE someMetric <> 'NaN'
GROUP BY someDimension
```

fails with on the Query tab:
Error: Unknown exception

While invoking method 'public org.apache.calcite.sql2rel.RelFieldTrimmer$TrimResult org.apache.calcite.sql2rel.RelFieldTrimmer.trimFields(org.apache.calcite.rel.core.Sort,org.apache.calcite.util.ImmutableBitSet,java.util.Set)'

java.lang.RuntimeException

stacktrace:

```
java.lang.RuntimeException: While invoking method 'public org.apache.calcite.sql2rel.RelFieldTrimmer$TrimResult org.apache.calcite.sql2rel.RelFieldTrimmer.trimFields(org.apache.calcite.rel.core.Sort,org.apache.calcite.util.ImmutableBitSet,java.util.Set)'
at org.apache.calcite.util.ReflectUtil$2.invoke(ReflectUtil.java:527) ~[calcite-core-1.21.0.jar:1.21.0]
at org.apache.calcite.sql2rel.RelFieldTrimmer.dispatchTrimFields(RelFieldTrimmer.java:272) ~[calcite-core-1.21.0.jar:1.21.0]
at org.apache.calcite.sql2rel.RelFieldTrimmer.trim(RelFieldTrimmer.java:161) ~[calcite-core-1.21.0.jar:1.21.0]
at org.apache.druid.sql.calcite.planner.Rules$DecorrelateAndTrimFieldsProgram.run(Rules.java:301) ~[druid-sql-0.20.0.jar:0.20.0]
at org.apache.calcite.tools.Programs$SequenceProgram.run(Programs.java:346) ~[calcite-core-1.21.0.jar:1.21.0]
at org.apache.calcite.tools.Programs$SequenceProgram.run(Programs.java:346) ~[calcite-core-1.21.0.jar:1.21.0]
at org.apache.calcite.prepare.PlannerImpl.transform(PlannerImpl.java:357) ~[calcite-core-1.21.0.jar:1.21.0]
at org.apache.druid.sql.calcite.planner.DruidPlanner.planWithDruidConvention(DruidPlanner.java:203) ~[druid-sql-0.20.0.jar:0.20.0]
at org.apache.druid.sql.calcite.planner.DruidPlanner.plan(DruidPlanner.java:137) ~[druid-sql-0.20.0.jar:0.20.0]
at org.apache.druid.sql.SqlLifecycle.plan(SqlLifecycle.java:168) ~[druid-sql-0.20.0.jar:0.20.0]
at org.apache.druid.sql.SqlLifecycle.plan(SqlLifecycle.java:179) ~[druid-sql-0.20.0.jar:0.20.0]
....
....
Caused by: java.lang.NumberFormatException
at java.math.BigDecimal.(BigDecimal.java:497) ~[?:1.8.0_302]
at java.math.BigDecimal.(BigDecimal.java:383) ~[?:1.8.0_302]
at java.math.BigDecimal.(BigDecimal.java:809) ~[?:1.8.0_302]
at java.math.BigDecimal.valueOf(BigDecimal.java:1277) ~[?:1.8.0_302]
at org.apache.druid.sql.calcite.planner.DruidRexExecutor.reduce(DruidRexExecutor.java:129) ~[druid-sql-0.20.0.jar:0.20.0]

```

Reproduce the SQL query using a GroupBy metric filtered against NaN, then inspect org.apache.druid.sql.calcite.planner.DruidRexExecutor.reduce and the planner path shown in the stack trace. Done means the query no longer throws RuntimeException or NumberFormatException during planning and returns the expected grouped result.

Written by the indexing model from the issue text.