Fix / disable several coreclr tests with interpreter

[janvorli]

This change contains the following:

• Fix cases when returning smaller than 32 bit int / uint values - introduce new INTOP_RET variants like Mono
• Fix index out of range check case when native int is used as an index to an array. To avoid adding an explosion of array element access IR opcodes, it adds a range check opcode that is used only when the index is nint.
• put back zeroing to INTOP_NEWOBJ_VT, few tests were failing because it was missing and we've already fixed the issue we had with the zeroing before by setting the "noCallArgs"
• Disable a test that uses pinvoke marshalling with calli

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[Copilot]

Pull Request Overview

This PR adds support for proper handling of small integer return types (int8, uint8, int16, uint16) and native integer (nint) array indexing in the CoreCLR interpreter.

• Added new return opcodes (RET_I1, RET_U1, RET_I2, RET_U2) to properly sign/zero extend small integer return values
• Implemented INTOP_CONV_NI to validate and convert nint values to int32 for array indexing operations
• Added memset initialization for value types before constructor calls to ensure deterministic behavior

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/tests/JIT/Regression/JitBlue/Runtime_58259/Runtime_58259.cs	Added ActiveIssue attribute to skip test on CoreCLR interpreter due to PInvoke marshalling issue
src/coreclr/interpreter/inc/intops.def	Added new opcode definitions for specialized return instructions and nint conversion
src/coreclr/vm/interpexec.cpp	Implemented execution logic for new return opcodes with proper type extension, INTOP_CONV_NI with range validation, and value type zero-initialization
src/coreclr/interpreter/compiler.h	Declared EmitNintIndexCheck helper function
src/coreclr/interpreter/compiler.cpp	Implemented GetRetForType, EmitNintIndexCheck, updated array operations to handle nint indices, fixed SUB_I4 condition, and updated validation for new return opcodes

[janvorli]

It seems something may be wrong with the nint index checking stuff based on my local libraries tests. It might be a red herring though. Let's wait with merging the change in until I can verify it.

[janvorli]

/ba-g the Android failures in the cryptography tests are unrelated to this change

[janvorli]

@kg, @davidwrighton, @BrzVlad I've fixed the problem in the nint index handling, now it works as expected based on my local testing. Can one of you take a look at this PR please?