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.

compiler/testData/diagnostics/testsWithStdLib/when/kt10192.kt

@@ -0,0 +1,20 @@
+fun test1() {
+    if (true) {
+        when (true) {
+            true -> println()
+        }
+    } else {
+        System.out?.println() // kotlin.Unit?
+    }
+}
+
+fun test2() {
+    val mlist = arrayListOf("")
+    if (true) {
+        when (true) {
+            true -> println()
+        }
+    } else {
+        mlist.add("") // kotlin.Boolean
+    }
+}