Remove LANGUAGE_VERSION from non-coroutine codegen tests

Most of these tests used this directive as a way to opt in to a new
language feature, and most of those features are already stable for a
long time, so no opt-in is needed. Some other tests used the directive
to opt out from a language feature, replace those by the `LANGUAGE`
directive. One test used the directive to test behavior that actually
depended on the API version; use `API_VERSION` directive there instead.

compiler/testData/codegen/box/jdk/stream.kt

@@ -1,9 +1,9 @@
-// SKIP_JDK6
+// JVM_TARGET: 1.8
 // IGNORE_BACKEND: JVM_IR
 // TARGET_BACKEND: JVM
 // FULL_JDK
 // WITH_RUNTIME
-// LANGUAGE_VERSION: 1.1
+
 import java.util.stream.*
 
 class B<F> : List<F> {