enhance assignments, booleans & conditionals (#5691)

test/compress/booleans.js

@@ -80,6 +80,25 @@ de_morgan_1c: {
     expect_stdout: "true"
 }
 
+de_morgan_1d: {
+    options = {
+        booleans: true,
+    }
+    input: {
+        function f(a) {
+            return (a = false) || a;
+        }
+        console.log(f(null), f(42));
+    }
+    expect: {
+        function f(a) {
+            return a = !1;
+        }
+        console.log(f(null), f(42));
+    }
+    expect_stdout: "false false"
+}
+
 de_morgan_2a: {
     options = {
         booleans: true,
@@ -181,6 +200,31 @@ de_morgan_2d: {
     ]
 }
 
+de_morgan_2e: {
+    options = {
+        booleans: true,
+        conditionals: true,
+    }
+    input: {
+        function f(a, b) {
+            return (a && b) && b;
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect: {
+        function f(a, b) {
+            return a && b;
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect_stdout: [
+        "null null",
+        "undefined {}",
+    ]
+}
+
 de_morgan_3a: {
     options = {
         booleans: true,