MdeModulePkg RegularExpressionDxe: Update Oniguruma to 6.9.0

https://bugzilla.tianocore.org/show_bug.cgi?id=1200
Update Oniguruma to the latest version v6.9.0.
Oniguruma https://github.com/kkos/oniguruma
Verify VS2017, GCC5 build.
Verify RegularExpressionProtocol GetInfo() and Match() function.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Dongao Guo <dongao.guo@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Reviewed-by: Cinnamon Shia <cinnamon.shia@hpe.com>

MdeModulePkg/Universal/RegularExpressionDxe/Oniguruma/st.h

@@ -10,9 +10,10 @@
 # include <windows.h>
 typedef ULONG_PTR st_data_t;
 #else
-typedef unsigned long st_data_t;
+// typedef unsigned long st_data_t;
 #endif
 #define ST_DATA_T_DEFINED
+typedef UINTN st_data_t;
 
 typedef struct st_table st_table;