Lint suggesting removing Null/Empty Message

Similar to #270 and #205 (both fixed apparently)

This happens with local `val`s (and `var`s) and using the `when` (and `if`) expressions in Kotlin.

Example:
```kt
return try {
val clazz = classLoader.loadClass(className) as Class
val constructor = clazz.getConstructor(Parameter::class.java)

constructor.newInstance(arg)
} catch (t: Throwable) {
val message = when(t) {
is ClassNotFoundException -> "Class ($className) not found"
is NoSuchMethodException -> "Matching constructor not found."
is InvocationTargetException -> "Constructor Invocation failed"
else -> "Unknown Error while instantiating Class"
}

// Use single-argument log method instead of null/empty message
Timber.e(t, message)
throw ReflectionException(message, t)
}
```

Start by reproducing the Kotlin example with local val/var variables inside when or if expressions and record the lint diagnostic. Compare the behavior with issues #270 and #205, then verify the diagnostic no longer incorrectly suggests removing the null or empty message in the shown Timber.e call.

Written by the indexing model from the issue text.