SPARK-1494 Don't initialize classes loaded by MIMA excludes, attempt 2

[WIP]

Looks like scala reflection was invoking the static initializer:
```
...
	at org.apache.spark.sql.test.TestSQLContext$.<init>(TestSQLContext.scala:25)
	at org.apache.spark.sql.test.TestSQLContext$.<clinit>(TestSQLContext.scala)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:270)
	at scala.reflect.runtime.JavaMirrors$JavaMirror.javaClass(JavaMirrors.scala:500)
	at scala.reflect.runtime.JavaMirrors$JavaMirror.tryJavaClass(JavaMirrors.scala:505)
	at scala.reflect.runtime.SymbolLoaders$PackageScope.lookupEntry(SymbolLoaders.scala:109)
...
```

Need to make sure that this doesn't change the exclusion semantics before merging.