Roll back "Use package:stack_trace in unittest."

pkg/unittest/lib/src/utils.dart

Index: pkg/unittest/lib/src/utils.dart
diff --git a/pkg/unittest/lib/src/utils.dart b/pkg/unittest/lib/src/utils.dart
index e10c597d3f0bda8623e088418d86b5f287e07aac..6442ac43897395373b96085e2444a1b512e1787c 100644
--- a/pkg/unittest/lib/src/utils.dart
+++ b/pkg/unittest/lib/src/utils.dart
@@ -46,24 +46,3 @@ String _escapeChar(String ch) {
     return ch;
 }
 
-/** Indent each line in [str] by two spaces. */
-String indent(String str) =>
-  str.replaceAll(new RegExp("^", multiLine: true), "  ");
-
-/** A pair of values. */
-class Pair<E, F> {
-  E first;
-  F last;
-
-  Pair(this.first, this.last);
-
-  String toString() => '($first, $last)';
-
-  bool operator==(other) {
-    if (other is! Pair) return false;
-    return other.first == first && other.last == last;
-  }
-
-  int get hashCode => first.hashCode ^ last.hashCode;
-}
-