Upgrade Scala to 2.12.15

[wangyum]

Description

Upgrade Scala to 2.12.15 to fix java.lang.IllegalArgumentException: too many arguments if running on JDK 17:

[info] Caused by: java.lang.reflect.InvocationTargetException
[info] 	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[info] 	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
[info] 	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[info] 	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
[info] 	at java.base/java.lang.invoke.SerializedLambda.readResolve(SerializedLambda.java:278)
[info] 	... 71 more
[info] Caused by: java.lang.IllegalArgumentException: too many arguments
[info] 	at java.base/java.lang.invoke.LambdaMetafactory.altMetafactory(LambdaMetafactory.java:511)
[info] 	at scala.runtime.LambdaDeserializer$.makeCallSite$1(LambdaDeserializer.scala:105)
[info] 	at scala.runtime.LambdaDeserializer$.deserializeLambda(LambdaDeserializer.scala:114)
[info] 	at scala.runtime.LambdaDeserialize.deserializeLambda(LambdaDeserialize.java:38)
[info] 	at org.apache.spark.sql.execution.LocalTableScanExec.$deserializeLambda$(LocalTableScanExec.scala)
[info] 	... 76 more

How was this patch tested?

Existing test.

Does this PR introduce any user-facing changes?

No.

[wangyum]

cc @zsxwing

[zsxwing]

LGTM. 2.12.15 is used by Spark 3.3.0 already: https://github.com/apache/spark/blob/v3.3.0/pom.xml#L160