Added a jasmine.exactly asymmetric equality tester

src/core/asymmetric_equality/Exactly.js

@@ -0,0 +1,17 @@
+getJasmineRequireObj().Exactly = function(j$) {
+  class Exactly {
+    constructor(expected) {
+      this.expected_ = expected;
+    }
+
+    asymmetricMatch(actual) {
+      return actual === this.expected_;
+    }
+
+    jasmineToString(pp) {
+      return `<jasmine.exactly(${pp(this.expected_)})>`;
+    }
+  }
+
+  return Exactly;
+};