Remove WITH_NEW_INFERENCE directive from all tests

This directive anyway does not make test run twice with OI, and with NI
It only once run the test with specific settings (// LANGUAGE)
and ignores irrelevant (OI or NI tags)

compiler/testData/diagnostics/tests/controlStructures/ForLoopWithExtensionIteratorOnNullable.kt

@@ -1,5 +1,4 @@
 // FIR_IDENTICAL
-// !WITH_NEW_INFERENCE
 // See also KT-7428
 class Container<K>(val k: K)
 // iterator() must be an extension, otherwise code will not compile