Support activating packages from local paths.

sdk/lib/_internal/pub/test/global/activate/constraint_with_path_test.dart

Index: sdk/lib/_internal/pub/test/global/activate/constraint_with_path_test.dart
diff --git a/sdk/lib/_internal/pub/test/global/deactivate/missing_package_arg_test.dart b/sdk/lib/_internal/pub/test/global/activate/constraint_with_path_test.dart
similarity index 50%
copy from sdk/lib/_internal/pub/test/global/deactivate/missing_package_arg_test.dart
copy to sdk/lib/_internal/pub/test/global/activate/constraint_with_path_test.dart
index 8cf9fc3056dff0769bc2fcdafab40643f832fc9e..d21a4ceb114f2e82ff507125ab73928143c6f973 100644
--- a/sdk/lib/_internal/pub/test/global/deactivate/missing_package_arg_test.dart
+++ b/sdk/lib/_internal/pub/test/global/activate/constraint_with_path_test.dart
@@ -7,13 +7,15 @@ import '../../test_pub.dart';
 
 main() {
   initConfig();
-  integration('fails if no package was given', () {
-    schedulePub(args: ["global", "deactivate"],
+  integration('fails if a version is passed with the path source', () {
+    schedulePub(args: ["global", "activate", "-spath", "foo", "1.2.3"],
         error: """
-            No package to deactivate given.
+            Unexpected argument "1.2.3".
 
-            Usage: pub global deactivate <package>
-            -h, --help    Print usage information for this command.
+            Usage: pub global activate [--source source] <package> [version]
+            -h, --help      Print usage information for this command.
+            -s, --source    The source used to find the package.
+                            [git, hosted (default), path]
 
             Run "pub help" to see global options.
             """,