EmulatorPkg: Add TpmMeasurementLib and AuthVariableLib library mapping

EmulatorPkg: Add TpmMeasurementLib and AuthVariableLib library mapping

These library classes are now linked with
MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
to optionally support secure variables.

For EmulatorPkg, secure boot is not currently enabled,
so we map these libraries to the NULL versions that don't support secure variables.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17761 6f19259b-4bc3-4df7-8a09-765794883524