Issue-475 : Using the unsigned operations where it s available on PrimitiveType

[PapisKang]

Fixes #475

On PrimitiveType.cs, PrimitiveTypeKind.UnsignedShort and PrimitiveTypeKind.UnsignedInt was using signed load operations.

On this pull request, i ve updated those operations to unsigned methods.

Base on tests i ve made in C#
Sign-Extension is used when loading a signed value
Zero-Extension when loading an unsigned.

Unsigned types are loaded with ldind.u* operations.

sbyte[] signedBytes = { -1 };
byte[] unsignedBytes = { 255 };

sbyte signedResult = signedBytes[0];
byte unsignedResult = unsignedBytes[0];

int signedInt = (int)signedResult;
int unsignedInt = (int)unsignedResult;

[ForNeVeR]

There's Ldind_U8 as well, can you update this one as well? Other than this, LGTM, thanks for fix and investigation!

[BadRyuner]

ldind_u8 does not exist.

[ForNeVeR]

Ah, I wasn't attentive enough when reading the instruction list. I double-checked it is present in the list, but missed the fact it's declared as an alias for ldind.i8.

[ForNeVeR]

Thanks!