improve parenthesis emission (#2196)

- eliminate `throw` usages
- suppress extraneous parenthesis
  - `new function() {foo.bar()}.baz`
  - `for (function() { "foo" in bar; };;);`

test/compress/loops.js

@@ -436,3 +436,17 @@ do_switch: {
         } while (false);
     }
 }
+
+in_parenthesis_1: {
+    input: {
+        for (("foo" in {});0;);
+    }
+    expect_exact: 'for(("foo"in{});0;);'
+}
+
+in_parenthesis_2: {
+    input: {
+        for ((function(){ "foo" in {}; });0;);
+    }
+    expect_exact: 'for(function(){"foo"in{}};0;);'
+}

test/compress/new.js

@@ -82,3 +82,19 @@ new_with_unary_prefix: {
     }
     expect_exact: 'var bar=(+new Date).toString(32);';
 }
+
+dot_parenthesis_1: {
+    input: {
+        console.log(new (Math.random().constructor) instanceof Number);
+    }
+    expect_exact: "console.log(new(Math.random().constructor)instanceof Number);"
+    expect_stdout: "true"
+}
+
+dot_parenthesis_2: {
+    input: {
+        console.log(typeof new function(){Math.random()}.constructor);
+    }
+    expect_exact: "console.log(typeof new function(){Math.random()}.constructor);"
+    expect_stdout: "function"
+}

test/compress/sequences.js

@@ -176,6 +176,11 @@ for_sequences: {
         // 4
         x = (foo in bar);
         for (y = 5; false;);
+        // 5
+        x = function() {
+            foo in bar;
+        };
+        for (y = 5; false;);
     }
     expect: {
         // 1
@@ -188,6 +193,10 @@ for_sequences: {
         // 4
         x = (foo in bar);
         for (y = 5; false;);
+        // 5
+        for (x = function() {
+            foo in bar;
+        }, y = 5; false;);
     }
 }