Add functionality to get full stack trace when exceptions are thrown.

tests/language/full_stacktrace3_test.dart

+void func1() {
+  throw new Exception("Test peanut gallery request for Full stacktrace");
+}
+void func2() {
+  func1();
+}
+void func3() {
+  try {
+    func2();
+  } on Object catch(e, s) {
+    print(e);
+    var full_trace = s.fullStacktrace;
+    Expect.isTrue(full_trace.contains("func1"));
+    Expect.isTrue(full_trace.contains("func2"));
+    Expect.isTrue(full_trace.contains("func3"));
+    Expect.isTrue(full_trace.contains("func4"));
+    Expect.isTrue(full_trace.contains("func5"));
+    Expect.isTrue(full_trace.contains("func6"));
+    Expect.isTrue(full_trace.contains("func7"));
+    Expect.isTrue(full_trace.contains("main"));
+
+    var trace = s.stacktrace;
+    Expect.isTrue(trace.contains("func1"));
+    Expect.isTrue(trace.contains("func2"));
+    Expect.isTrue(trace.contains("func3"));
+
+    Expect.isFalse(trace.contains("func4"));
+    Expect.isFalse(trace.contains("func5"));
+    Expect.isFalse(trace.contains("func6"));
+    Expect.isFalse(trace.contains("func7"));
+    Expect.isFalse(trace.contains("main"));
+
+    print("Full stack trace");
+    print(full_trace);
+    print("Stack trace");
+    print(trace);
+    throw new Exception("This is not a rethrow");
+  }
+}
+int func4() {
+  func3();
+  return 1;
+}
+int func5() {
+  try {
+    func4();
+  } on Object catch(e, s) {
+    var full_trace = s.fullStacktrace;
+    Expect.isFalse(full_trace.contains("func1"));
+    Expect.isFalse(full_trace.contains("func2"));
+    Expect.isTrue(full_trace.contains("func3"));
+    Expect.isTrue(full_trace.contains("func4"));
+    Expect.isTrue(full_trace.contains("func5"));
+    Expect.isTrue(full_trace.contains("func6"));
+    Expect.isTrue(full_trace.contains("func7"));
+    Expect.isTrue(full_trace.contains("main"));
+
+    var trace = s.stacktrace;
+    Expect.isFalse(trace.contains("func1"));
+    Expect.isFalse(trace.contains("func2"));
+
+    Expect.isTrue(trace.contains("func3"));
+    Expect.isTrue(trace.contains("func4"));
+    Expect.isTrue(trace.contains("func5"));
+
+    Expect.isFalse(trace.contains("func6"));
+    Expect.isFalse(trace.contains("func7"));
+    Expect.isFalse(trace.contains("main"));
+
+    print("Full stack trace");
+    print(full_trace);
+    print("Stack trace");
+    print(trace);
+  }
+  return 1;
+}
+int func6() {
+  func5();
+  return 1;
+}
+int func7() {
+  func6();
+  return 1;
+}
+main() {
+  var i = func7();
+  Expect.equals(1, i);
+}