[FIR] Fix false positive RETURN_TYPE_MISMATCH in intellij ultimate

compiler/testData/diagnostics/tests/functionLiterals/return/IfWithoutElseWithExplicitType.fir.kt

@@ -5,7 +5,7 @@ val a: () -> Int = <!INITIALIZER_TYPE_MISMATCH!>l@ {
 }<!>
 
 val b: () -> Unit = l@ {
-    if (flag) return@l <!RETURN_TYPE_MISMATCH!>4<!>
+    if (flag) return@l 4
 }
 
 val c: () -> Any = l@ {

compiler/testData/diagnostics/tests/functionLiterals/return/LocalReturnSecondUnit.fir.kt

@@ -0,0 +1,6 @@
+val flag = true
+
+val a = b@ {
+    if (flag) return@b 4
+    return@b
+}

compiler/testData/diagnostics/tests/functionLiterals/return/LocalReturnSecondUnit.kt

@@ -1,7 +1,6 @@
-// FIR_IDENTICAL
 val flag = true
 
 val a = b@ {
     if (flag) return@b <!RETURN_TYPE_MISMATCH!>4<!>
     return@b
-}
+}

compiler/testData/diagnostics/tests/functionLiterals/return/LocalReturnsWithExplicitReturnType.fir.kt

@@ -1,6 +1,6 @@
 fun test(a: Int) {
     run<Int>f@{
-      if (a > 0) return@f <!ARGUMENT_TYPE_MISMATCH, RETURN_TYPE_MISMATCH!>""<!>
+      if (a > 0) return@f <!ARGUMENT_TYPE_MISMATCH!>""<!>
       return@f 1
     }