Replace all occurrences of WITH_RUNTIME with WITH_STDLIB

We are going to deprecate `WITH_RUNTIME` directive. The main reason
behind this change is that `WITH_STDLIB` directive better describes
its meaning, specifically it will add kotlin stdlib to test's classpath.

compiler/testData/diagnostics/tests/delegation/kt44843.fir.kt

@@ -1,4 +1,4 @@
-// WITH_RUNTIME
+// WITH_STDLIB
 
 // FILE: test.kt
 val bar2 by bar2(<!NO_VALUE_FOR_PARAMETER!>)<!>

compiler/testData/diagnostics/tests/delegation/kt44843.kt

@@ -1,4 +1,4 @@
-// WITH_RUNTIME
+// WITH_STDLIB
 
 // FILE: test.kt
 val bar2 by <!TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM!><!DEBUG_INFO_MISSING_UNRESOLVED!>bar2<!>()<!>