Fix optimization in JS BE

Don't apply while condition folding when corresponding break
statement breaks outer loop.

js/js.inliner/src/org/jetbrains/kotlin/js/inline/clean/WhileConditionFolding.kt

@@ -105,7 +105,7 @@ class WhileConditionFolding(val body: JsBlock) {
                 // therefore for single `break` we should return `false`.
                 is JsBreak -> {
                     val target = statement.label?.name
-                    if (label == null || label == target) JsLiteral.FALSE else null
+                    if (label == target) JsLiteral.FALSE else null
                 }
 
                 // Code like this

js/js.tests/test/org/jetbrains/kotlin/js/test/optimizer/WhileConditionFoldingTest.kt

@@ -40,4 +40,6 @@ class WhileConditionFoldingTest : BasicOptimizerTest("while-condition-folding")
     @Test fun doWhileWithNestedContinue() = box()
 
     @Test fun labeledContinueInNestedLoop() = box()
+
+    @Test fun labeledBreak() = box()
 }

js/js.translator/testData/js-optimizer/while-condition-folding/labeledBreak.optimized.js

@@ -0,0 +1,19 @@
+function box() {
+    var i = 0;
+    var j = 0;
+    var log = "";
+    outer: while (i < 10) {
+        while (j < 10) {
+            if (i + j >= 3) {
+                break outer;
+            }
+            log += i + "," + j + ";";
+            j++;
+        }
+        i++;
+    }
+
+    if (log != "0,0;0,1;0,2;") return "fail: " + log;
+
+    return "OK"
+}

js/js.translator/testData/js-optimizer/while-condition-folding/labeledBreak.original.js

@@ -0,0 +1,19 @@
+function box() {
+    var i = 0;
+    var j = 0;
+    var log = "";
+    outer: while (i < 10) {
+        while (j < 10) {
+            if (i + j >= 3) {
+                break outer;
+            }
+            log += i + "," + j + ";";
+            j++;
+        }
+        i++;
+    }
+
+    if (log != "0,0;0,1;0,2;") return "fail: " + log;
+
+    return "OK"
+}