WhenWithOnlyElse: don't remove when subject variable if needed

#KT-30975 Fixed

idea/testData/inspectionsLocal/whenWithOnlyElse/subjectVariable/blockElseUsedAsExpression/multiReference.kt

@@ -0,0 +1,12 @@
+// WITH_RUNTIME
+fun test() {
+    val x = when (val a = create()) {
+        else -> {
+            use(a, a)
+        }
+    }<caret>
+}
+
+fun create(): String = ""
+
+fun use(s: String, t: String) {}

idea/testData/inspectionsLocal/whenWithOnlyElse/subjectVariable/blockElseUsedAsExpression/multiReference.kt.after

@@ -0,0 +1,11 @@
+// WITH_RUNTIME
+fun test() {
+    val x = <caret>run {
+        val a = create()
+        use(a, a)
+    }
+}
+
+fun create(): String = ""
+
+fun use(s: String, t: String) {}

idea/testData/inspectionsLocal/whenWithOnlyElse/subjectVariable/blockElseUsedAsExpression/noReference.kt

@@ -0,0 +1,12 @@
+// WITH_RUNTIME
+fun test() {
+    val x = when (val a = create()) {
+        else -> {
+            use("")
+        }
+    }<caret>
+}
+
+fun create(): String = ""
+
+fun use(s: String) {}

idea/testData/inspectionsLocal/whenWithOnlyElse/subjectVariable/blockElseUsedAsExpression/noReference.kt.after

@@ -0,0 +1,11 @@
+// WITH_RUNTIME
+fun test() {
+    val x = <caret>run {
+        val a = create()
+        use("")
+    }
+}
+
+fun create(): String = ""
+
+fun use(s: String) {}

idea/testData/inspectionsLocal/whenWithOnlyElse/subjectVariable/blockElseUsedAsExpression/noReference2.kt

@@ -0,0 +1,10 @@
+// WITH_RUNTIME
+fun test() {
+    val x = when (val a = 42) {
+        else -> {
+            use("")
+        }
+    }<caret>
+}
+
+fun use(s: String) {}

idea/testData/inspectionsLocal/whenWithOnlyElse/subjectVariable/blockElseUsedAsExpression/noReference2.kt.after

@@ -0,0 +1,8 @@
+// WITH_RUNTIME
+fun test() {
+    val x = <caret>run {
+        use("")
+    }
+}
+
+fun use(s: String) {}

idea/testData/inspectionsLocal/whenWithOnlyElse/subjectVariable/blockElseUsedAsExpression/singleReference.kt

@@ -0,0 +1,12 @@
+// WITH_RUNTIME
+fun test() {
+    val x = when (val a = create()) {
+        else -> {
+            use(a)
+        }
+    }<caret>
+}
+
+fun create(): String = ""
+
+fun use(s: String) {}

idea/testData/inspectionsLocal/whenWithOnlyElse/subjectVariable/blockElseUsedAsExpression/singleReference.kt.after

@@ -0,0 +1,10 @@
+// WITH_RUNTIME
+fun test() {
+    val x = <caret>run {
+        use(create())
+    }
+}
+
+fun create(): String = ""
+
+fun use(s: String) {}