Java: Don't offer "Unwrap 'else' branch" intention if it might cause unreachable code (IDEA-165428)

java/java-tests/testData/codeInsight/unwrapElseBranch/beforeLabeled2.java

@@ -0,0 +1,15 @@
+// "Unwrap 'else' branch (changes semantics)" "false"
+
+class T {
+    void f(boolean b) {
+        Label:
+        {
+            if (b)
+                System.out.println("When true");
+            <caret>else {
+                throw new RuntimeException("Otherwise");
+            }
+        }
+        System.out.println("Done");
+    }
+}