DPE: Update tests following the spec changes

As per spec updates in v1.0 r9:
* Rename DeriveChild to DeriveContext.
* Rename its input argument allow_child_to_derive to
    allow_new_context_to_derive.
* Add new input and output arguments

Further, separate DeriveContext core functionality test removed since
already covered by CertifyKey command.

Signed-off-by: Maulik Patel <maulik.patel@arm.com>
Change-Id: I397c61fd30cfe9119768d78c597f4682a8155df7
9 files changed