Bazel: Fix lint warning flagged by buildifier

Bazel: Fix lint warning flagged by buildifier

This change is fixing confusing name warning: [1].

  ./org.eclipse.jgit.test/tests.bzl:12: confusing-name:
  Never use 'l', 'I', or 'O' as names (they're too easily confused
  with 'I', 'l', or '0').

And is also fixing: "All calls to rules or macros should pass arguments
by keyword position argument" warning: [2].

  ./org.eclipse.jgit.test/BUILD:42: positional-args: All calls to rules
  or macros should pass arguments by keyword (arg_name=value) syntax.

[1] https://github.com/bazelbuild/buildtools/blob/master/WARNINGS.md#confusing-name
[2] https://github.com/bazelbuild/buildtools/blob/master/WARNINGS.md#positional-args

Change-Id: If5c28ec8a1ddc1d1b1035bd07b838a2a564aea4f
Signed-off-by: David Ostrovsky <david@ostrovsky.org>