MdeModulePkg: DxeMain: Check memory type overlap inside CoreGetMemoryMap

This change adds validation to CoreGetMemoryMap to ensure that special
memory bins are fully respected. Specifically, any memory map entry that
falls within a special bin must be entirely contained within that bin,
and its memory type must match the bin's designated type.

This check helps preventing unintended changes that could cause the
system memory map to cross bin boundaries unexpectedly.

Signed-off-by: Kun Qin <kun.qin@microsoft.com>