Deprecate simplification of complex boolean constant expressions in whens and loops

^KT-39883 In Progress

compiler/testData/diagnostics/tests/when/exhaustiveBooleanWhenWithUntrivialConst_error.kt

@@ -0,0 +1,32 @@
+// FIR_IDENTICAL
+// !LANGUAGE: +ProhibitSimplificationOfNonTrivialConstBooleanExpressions
+// ISSUE: KT-39883
+
+// Should always work
+fun test_0(b: Boolean): String = when (b) {
+    true -> "true"
+    false -> "false"
+}
+
+// Deprecated
+fun test_1(b: Boolean): String = <!NO_ELSE_IN_WHEN!>when<!> (b) {
+    1 == 1 -> "true"
+    "" != "" -> "false"
+}
+
+const val TRUE = true
+
+// Already not working
+fun test_2(b: Boolean): String = <!NO_ELSE_IN_WHEN!>when<!>(b) {
+    TRUE -> "true"
+    false -> "false"
+}
+
+const val s1 = "s1"
+const val s2 = "s2"
+
+// Already not working
+fun test_3(b: Boolean): String = <!NO_ELSE_IN_WHEN!>when<!>(b) {
+    true -> "true"
+    s1 == s2 -> "false"
+}