MdeModulePkg: MemoryBins: make GoogleTest page-granularity aware

MemoryBinGoogleTest.PopulatesFromValidHob asserted fixed page counts for
each memory type.  PopulateMemoryTypeInformation, however, rounds the
runtime memory types (EfiReservedMemoryType, EfiACPIMemoryNVS,
EfiRuntimeServicesCode, EfiRuntimeServicesData) up to
RUNTIME_PAGE_ALLOCATION_GRANULARITY.  That granularity equals EFI_PAGE_SIZE
on IA32/X64, so the hard-coded values happened to match, but it is 64 KiB
on AArch64, where the same inputs round up to different page counts and the
test failed.

Compute the expected page counts with the same granularity rounding the
production code uses, so the test passes on all host architectures instead
of only x86.

Signed-off-by: Jeff Brasen <jbrasen@nvidia.com>