Handle stack traces that don't give column numbers (#4016)

packages/flutter_test/lib/src/stack_manipulation.dart

@@ -15,7 +15,7 @@ int reportExpectCall(StackTrace stack, StringBuffer information) {
   final RegExp line0 = new RegExp(r'^#0 +fail \(.+\)$');
   final RegExp line1 = new RegExp(r'^#1 +expect \(.+\)$');
   final RegExp line2 = new RegExp(r'^#2 +expect \(.+\)$');
-  final RegExp line3 = new RegExp(r'^#3 +[^(]+ \((.+):([0-9]+):[0-9]+\)$');
+  final RegExp line3 = new RegExp(r'^#3 +[^(]+ \((.+?):([0-9]+)(?::[0-9]+)?\)$');
   final List<String> stackLines = stack.toString().split('\n');
   if (line0.firstMatch(stackLines[0]) != null &&
       line1.firstMatch(stackLines[1]) != null &&

packages/flutter_test/test/stack_manipulation_test.dart

@@ -8,6 +8,7 @@ void main() {
   test('stack manipulation: reportExpectCall', () {
     try {
       expect(false, isTrue);
+      throw 'unexpectedly did not throw';
     } catch (e, stack) {
       StringBuffer information = new StringBuffer();
       expect(reportExpectCall(stack, information), 3);