Fix CilPurityClassifier misclassifying several opcodes

[wondercrash]

Added missing cases to ClassifyInlineNone :

• stind.r4 and stind.ref were missing
• cpblk and initblk are pointer writes
• throw and rethrow should be impure
• localloc is impure since its similar to newarr (allocates and pushes a pointer)

Added cpobj, initobj, and stobj to ClassifyInlineType as pointer writes

Using DefaultTypeAccessPurity for stelem doesn't really make sense to me since stelem doesn't really access a type, it just uses it to get the size of the element I believe.

Echo/src/Platforms/Echo.Platforms.AsmResolver/CilPurityClassifier.cs

Lines 274 to 275 in 6796b43

	case CilCode.Stelem:
	return ArrayWritePurity | DefaultTypeAccessPurity;

dnlib's CilPurityClassifier was outdated so I ported over AsmResolver's along with the changes.

I wouldn't mind feedback on these changes though

[Washi1337]

Interesting, I was under the impression ldelem/stelem/cpobj/etc would trigger a type class constructor call (and thus would be a type access purity), but it seems not to be the case (In fact, on Mono, not even <Module>::.cctor is necessarily called, even when the type is loaded from an external DLL).

Thanks