Fix type inference issues for 'if' and 'when'.

Use 'expectedType' (when present) as an explicit type argument for a special construct call.
Unfortunately, this approach can't be used for elvis due to other elvis-related inference hacks.
Fixes KT-10807, KT-10811.
This also affects KT-6189: now we can infer proper type for 'if'.

If type inference for special call failed, and we found no type errors in sub-expressions,
report TYPE_INFERENCE_FAILED_ON_SPECIAL_CONSTRUCT error.
This (and the hack above) fixes KT-10809: code no longer compiles.

idea/ide-common/src/org/jetbrains/kotlin/idea/codeInsight/ReferenceVariantsHelper.kt

@@ -197,7 +197,7 @@ class ReferenceVariantsHelper(
         }
 
         if (callType == CallType.SUPER_MEMBERS) { // we need to unwrap fake overrides in case of "super." because ShadowedDeclarationsFilter does not work correctly
-            return descriptors.flatMapTo(LinkedHashSet()) {
+            return descriptors.flatMapTo(LinkedHashSet<DeclarationDescriptor>()) {
                 if (it is CallableMemberDescriptor && it.kind == CallableMemberDescriptor.Kind.FAKE_OVERRIDE) it.overriddenDescriptors else listOf(it)
             }
         }