Refactor service tests in preparation of running on sky_shell

runtime/observatory/tests/service/parameters_in_scope_at_entry_test.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 // VMOptions=--error_on_bad_type --error_on_bad_override  --verbose_debug
 
 import 'package:observatory/service_io.dart';
 import 'test_helper.dart';
 import 'dart:developer';
 import 'package:unittest/unittest.dart';
 
+import 'service_test_common.dart';
+
+const int LINE_A = 29;
+const int LINE_B = 33;
+
 foo(param) {
   return param;
 }
 
 fooClosure() {
   theClosureFunction(param) {
     return param;
   }
   return theClosureFunction;
 }
 
 testMain() {
   debugger();
-  foo("in-scope");  // Line 24
+  foo("in-scope");  // Line A.
 
   var f = fooClosure();
   debugger();
-  f("in-scope");  // Line 28
+  f("in-scope");  // Line B.
 }
 
 var tests = [
   hasStoppedAtBreakpoint,
-  stoppedAtLine(24),
+  stoppedAtLine(LINE_A),
   (isolate) => isolate.stepInto(),
   hasStoppedAtBreakpoint,
   (isolate) async {
     var stack = await isolate.getStack();
     Frame top = stack['frames'][0];
     print(top);
     expect(top.function.name, equals("foo"));
     print(top.variables);
     expect(top.variables.length, equals(1));
     var param = top.variables[0];
     expect(param['name'], equals("param"));
     expect(param['value'].valueAsString, equals("in-scope"));
   },
   resumeIsolate,
 
   hasStoppedAtBreakpoint,
-  stoppedAtLine(28),
+  stoppedAtLine(LINE_B),
   (isolate) => isolate.stepInto(),
   hasStoppedAtBreakpoint,
   (isolate) async {
     var stack = await isolate.getStack();
     Frame top = stack['frames'][0];
     print(top);
     expect(top.function.name, equals("theClosureFunction"));
     print(top.variables);
     expect(top.variables.length, equals(1));
     var param = top.variables[0];
     expect(param['name'], equals("param"));
     expect(param['value'].valueAsString, equals("in-scope"));
   },
   resumeIsolate,
 ];
 
 main(args) => runIsolateTests(args, tests, testeeConcurrent: testMain);