MdeModulePkg/UdfDxe: Use debug msg instead of ASSERT in UdfOpen()
MdeModulePkg/UdfDxe: Use debug msg instead of ASSERT in UdfOpen()

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1248

Within function UdfOpen():
This commit will use debug messages instead of using ASSERT when an error
occurs after calling GetFileSize().

Cc: Ruiyu Ni <9fa3a6894a36bca79e6a72ad65af5a5702efecd1@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Hao Wu <f387b71200577e27ccf5abb090fda0ddd187ec6e@intel.com>
Reviewed-by: Paulo Alcantara <50d86b744cb102417077bd909520bfbee0f43976@suse.de>
Reviewed-by: Star Zeng <5c6bb72efe464613af94e84c05522a361b23844a@intel.com>

MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2