contrib/elf2dmp: add PE name check and Windows Server 2022 support

contrib/elf2dmp: add PE name check and Windows Server 2022 support

Since its inception elf2dmp has checked MZ signatures within an
address space above IDT[0] interrupt vector and took first PE image
found as Windows Kernel.
But in Windows Server 2022 memory dump this address space range is
full of invalid PE fragments and the tool must check that PE image
is 'ntoskrnl.exe' actually.
So, introduce additional validation by checking image name from
Export Directory against 'ntoskrnl.exe'.

Signed-off-by: Viktor Prutyanov <viktor@daynix.com>
Tested-by: Yuri Benditovich <yuri.benditovich@daynix.com>
Reviewed-by: Annie Li <annie.li@oracle.com>
Message-id: 20230222211246.883679-4-viktor@daynix.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>