Fix overflow-checks test for RISC-V target

[ZhongyaoChen]

The overflow-checks codegen test was failing on riscv64gc target because the FileCheck pattern did not account for ABI extension attributes. RISC-V LP64 ABI requires integer types smaller than XLEN (64-bit) to be zero-extended or sign-extended to register width.

For u8 parameters, RISC-V generates:
i8 noundef zeroext %a, i8 noundef zeroext %b

While x86_64 and aarch64 generate:
i8 noundef %a, i8 noundef %b

The original CHECK pattern only matched the format without the zeroext attribute, causing test failures on RISC-V.

This patch makes the zeroext attribute optional in the FileCheck pattern using {{( zeroext)?}}, allowing the test to pass on architectures that add ABI extension attributes (e.g., RISC-V).

Test results before fix:

• x86_64-unknown-linux-gnu: 3 passed
• aarch64-unknown-linux-gnu: 3 passed
• riscv64gc-unknown-linux-gnu: 1 passed, 2 failed

Test results after fix:

• x86_64-unknown-linux-gnu: 3 passed
• aarch64-unknown-linux-gnu: 3 passed
• riscv64gc-unknown-linux-gnu: 3 passed

[rustbot]

r? @Mark-Simulacrum

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[Mark-Simulacrum]

@bors r+ rollup

[bors]

📌 Commit eef09cf has been approved by Mark-Simulacrum

It is now in the queue for this repository.