[IDEA-TESTS] Specify language version in feature-dependent tests

Some quickfixes are relying on diagnostics, that won't be reported
with new language features enabled.
`MixedNamedArgumentsInTheirOwnPosition`
`AllowBreakAndContinueInsideWhen`

idea/testData/quickfix/checkArguments/addNameToArgument/mixedNamedAndPositionalArgumentsMultiple.kt

@@ -1,4 +1,6 @@
 // "Add name to argument..." "true"
+// LANGUAGE_VERSION: 1.3
+
 fun f(a: Int, b: String = "b", c: String = "c") {}
 
 fun g() {