LibJS: Implement bitwise left shift operator (<<)

Author: https://github.com/linusg
Commit: f0e7404480
Pull-request: https://github.com/SerenityOS/serenity/pull/1931
Reviewed-by: https://github.com/awesomekling

Libraries/LibJS/Tests/binary-bitwise-left-shift.js

@@ -0,0 +1,63 @@
+load("test-common.js");
+
+try {
+    assert((0 << 0) === 0);
+    assert((0 << 1) === 0);
+    assert((0 << 2) === 0);
+    assert((0 << 3) === 0);
+    assert((0 << 4) === 0);
+    assert((0 << 5) === 0);
+
+    assert((1 << 0) === 1);
+    assert((1 << 1) === 2);
+    assert((1 << 2) === 4);
+    assert((1 << 3) === 8);
+    assert((1 << 4) === 16);
+    assert((1 << 5) === 32);
+
+    assert((2 << 0) === 2);
+    assert((2 << 1) === 4);
+    assert((2 << 2) === 8);
+    assert((2 << 3) === 16);
+    assert((2 << 4) === 32);
+    assert((2 << 5) === 64);
+
+    assert((3 << 0) === 3);
+    assert((3 << 1) === 6);
+    assert((3 << 2) === 12);
+    assert((3 << 3) === 24);
+    assert((3 << 4) === 48);
+    assert((3 << 5) === 96);
+
+    assert((4 << 0) === 4);
+    assert((4 << 1) === 8);
+    assert((4 << 2) === 16);
+    assert((4 << 3) === 32);
+    assert((4 << 4) === 64);
+    assert((4 << 5) === 128);
+
+    assert((5 << 0) === 5);
+    assert((5 << 1) === 10);
+    assert((5 << 2) === 20);
+    assert((5 << 3) === 40);
+    assert((5 << 4) === 80);
+    assert((5 << 5) === 160);
+
+    var x = 3;
+    var y = 7;
+    assert(("42" << 6) === 2688);
+    assert((x << y) === 384);
+    assert((x << [[[[12]]]]) === 12288);
+    assert((undefined << y) === 0);
+    assert(("a" << "b") === 0);
+    assert((null << null) === 0);
+    assert((undefined << undefined) === 0);
+    assert((NaN << NaN) === 0);
+    assert((NaN << 6) === 0);
+    assert((Infinity << Infinity) === 0);
+    assert((-Infinity << Infinity) === 0);
+
+    console.log("PASS");
+} catch (e) {
+    console.log("FAIL: " + e);
+}