[bazel] Skip ConfigTest#testCommitTemplatePathInHomeDirecory

[bazel] Skip ConfigTest#testCommitTemplatePathInHomeDirecory

Move this test to another class and skip it when running tests with
bazel since the bazel test runner does not allow to create files in the
home directory.

FS#userHome retrieves the home directory on the first call and caches it
for subsequent calls to avoid overhead in case path translation is
required (currently on cygwin). This prevents that the test can mock the
home directory using MockSystemReader like SshTestHarness does.

Change-Id: I6a22f37f4a19eb4b4935509eae508a23e56db7aa