StandaloneMmPkg/StandaloneMmCoreEntryPoint: relocate StMM core on the fly

StandaloneMmPkg/StandaloneMmCoreEntryPoint: relocate StMM core on the fly

Apply PE/COFF fixups when starting up the standalone MM core, so that
it can execute at any address regardless of the link time address.

Note that this requires the PE/COFF image to be emitted with its
relocation section preserved. Special care is taken to ensure that
TE images are dealt with correctly as well.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
Acked-by: Jiewen Yao <Jiewen.yao@intel.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>