improve AST_For.init & AST_Switch.expression compression (#2546)

test/compress/loops.js

@@ -452,3 +452,19 @@ in_parenthesis_2: {
     }
     expect_exact: 'for(function(){"foo"in{}};0;);'
 }
+
+init_side_effects: {
+    options = {
+        loops: true,
+        side_effects: true,
+    };
+    input: {
+        for (function() {}(), i = 0; i < 5; i++) console.log(i);
+        for (function() {}(); i < 10; i++) console.log(i);
+    }
+    expect: {
+        for (i = 0; i < 5; i++) console.log(i);
+        for (; i < 10; i++) console.log(i);
+    }
+    expect_stdout: true
+}

test/compress/sequences.js

@@ -252,13 +252,12 @@ negate_iife_for: {
     input: {
         (function() {})();
         for (i = 0; i < 5; i++) console.log(i);
-
         (function() {})();
-        for (; i < 5; i++) console.log(i);
+        for (; i < 10; i++) console.log(i);
     }
     expect: {
         for (!function() {}(), i = 0; i < 5; i++) console.log(i);
-        for (function() {}(); i < 5; i++) console.log(i);
+        for (!function() {}(); i < 10; i++) console.log(i);
     }
     expect_stdout: true
 }

test/compress/switch.js

@@ -817,3 +817,23 @@ issue_1758: {
     }
     expect_stdout: "0 3"
 }
+
+issue_2535: {
+    options = {
+        evaluate: true,
+        dead_code: true,
+        switches: true,
+    }
+    input: {
+        switch(w(), 42) {
+            case 13: x();
+            case 42: y();
+            default: z();
+        }
+    }
+    expect: {
+        w(), 42;
+        y();
+        z();
+    }
+}