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/bytecodeText/nullCheckOptimization/localLateinit/checkedAlways.kt

@@ -1,5 +1,3 @@
-// LANGUAGE_VERSION: 1.2
-
 fun almostAlwaysTrue() = true
 
 fun runNoInline(f: () -> Unit) = f()
@@ -23,4 +21,4 @@ fun test() {
 
 // 0 IFNULL
 // 3 IFNONNULL
-// 3 throwUninitializedPropertyAccessException
+// 3 throwUninitializedPropertyAccessException

compiler/testData/codegen/bytecodeText/nullCheckOptimization/localLateinit/checkedOnce.kt

@@ -1,5 +1,3 @@
-// LANGUAGE_VERSION: 1.2
-
 fun almostAlwaysTrue() = true
 
 fun test() {
@@ -16,4 +14,4 @@ fun test() {
 
 // 0 IFNULL
 // 1 IFNONNULL
-// 1 throwUninitializedPropertyAccessException
+// 1 throwUninitializedPropertyAccessException

compiler/testData/codegen/bytecodeText/nullCheckOptimization/localLateinit/initialized.kt

@@ -1,5 +1,3 @@
-// LANGUAGE_VERSION: 1.2
-
 fun test() {
     lateinit var z: String
     run {
@@ -9,4 +7,4 @@ fun test() {
 }
 
 // 0 IFNULL
-// 0 IFNONNULL
+// 0 IFNONNULL