[NI] Remove hack for special functions

Treating special functions for `if`, `when`, `try`, `?:` as not accepting `Nothing` result type is incorrect.
Making so leads to cases with uninferred `Nothing` result type for inner calls and lost data flow info.

compiler/testData/diagnostics/tests/controlFlowAnalysis/elvisNotProcessed.kt

@@ -15,7 +15,7 @@ val ww = if (true) {
     <!OI;TYPE_MISMATCH!>{ true }<!> <!USELESS_ELVIS!>?: null!!<!>
 }
 else if (true) {
-    <!OI;TYPE_MISMATCH!>{ true }<!> <!USELESS_ELVIS!>?: null!!<!>
+    <!NI;TYPE_MISMATCH, NI;TYPE_MISMATCH, TYPE_MISMATCH!>{ <!NI;CONSTANT_EXPECTED_TYPE_MISMATCH!>true<!> }<!> <!USELESS_ELVIS!>?: null!!<!>
 }
 else {
     null!!

compiler/testData/diagnostics/tests/regressions/kt32836.fir.kt

@@ -1,4 +1,5 @@
 // !DIAGNOSTICS: -UNUSED_PARAMETER
+// !WITH_NEW_INFERENCE
 
 inline fun <reified T> parse(json: String): T? = TODO()
 

compiler/testData/diagnostics/tests/regressions/kt32836.kt

@@ -1,4 +1,5 @@
 // !DIAGNOSTICS: -UNUSED_PARAMETER
+// !WITH_NEW_INFERENCE
 
 inline fun <reified T> parse(json: String): T? = TODO()
 
@@ -6,7 +7,7 @@ class MyType
 
 fun parseMyData(json: String): MyType =
     try {
-        parse(json) // error with new inf only: Cannot use 'Nothing?' as reified type parameter
+        <!NI;REIFIED_TYPE_FORBIDDEN_SUBSTITUTION, NI;REIFIED_TYPE_FORBIDDEN_SUBSTITUTION!>parse<!>(json) // error with new inf only: Cannot use 'Nothing?' as reified type parameter
             ?: throw IllegalArgumentException("Can't parse")
     } catch (e: Exception) {
         throw IllegalArgumentException("Can't parse")

compiler/testData/diagnostics/tests/regressions/testNestedSpecialCalls.fir.kt

@@ -0,0 +1,11 @@
+// !LANGUAGE: +NewInference
+// !DIAGNOSTICS: -UNUSED_PARAMETER -UNREACHABLE_CODE
+
+fun test() {
+    val x: Int? = 20
+    if (x != null) {
+    } else {
+        if (true) return else return
+    }
+    x.and(1) // unsafe call
+}

compiler/testData/diagnostics/tests/regressions/testNestedSpecialCalls.kt

@@ -0,0 +1,11 @@
+// !LANGUAGE: +NewInference
+// !DIAGNOSTICS: -UNUSED_PARAMETER -UNREACHABLE_CODE
+
+fun test() {
+    val x: Int? = 20
+    if (x != null) {
+    } else {
+        if (true) return else return
+    }
+    <!DEBUG_INFO_SMARTCAST!>x<!>.and(1) // unsafe call
+}

compiler/testData/diagnostics/tests/regressions/testNestedSpecialCalls.txt

@@ -0,0 +1,3 @@
+package
+
+public fun test(): kotlin.Unit