MdeModulePkg/RegularExpressionDxe: Optimize the code infrastructure

MdeModulePkg/RegularExpressionDxe: Optimize the code infrastructure

OnigurumaIntrinsics.c is now not used. So the implement of function
'memcpy' is now not., which causes build failure with CLANG9 and
XCODE. I remove OnigurumaIntrinsics.c and move the necessary function
implement to OnigurumaUefiPort.c/h.

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Signed-off-by: Shenglei Zhang <shenglei.zhang@intel.com>
Reviewed-by: Jian J Wang <jian.j.wang@intel.com>