Add keystore2_key namespace `shell_key` for `shell`.

Add a keystore2_key namespace that can be used by `shell` for testing.

Bug: 158500146
Bug: 162265751
Test: keystore2_test
Change-Id: I78b9b285969dd503a09609f7bcb02552b24d1a6b
Merged-In: I78b9b285969dd503a09609f7bcb02552b24d1a6b
3 files changed