Add Zicfiss extension tests

[ved-rivos]

Description

Implements tests for Zicfiss extension.
Tests sspush, sspopchk, ssamoswap, ssrdp, c_sspush, and c_sspopchk instructions in S and U mode
Specification: https://github.com/riscv/riscv-cfi/blob/main/cfi_backward.adoc

Related Issues

N/A

Ratified/Unratified Extensions

• Ratified
• Unratified

List Extensions

Zicfiss: https://github.com/riscv/riscv-cfi/blob/main/cfi_backward.adoc

Reference Model Used

• SAIL
• Spike
• Other - < SPECIFY HERE >

Mandatory Checklist:

• All tests are compliant with the test-format spec present in this repo ?
• Ran the new tests on RISCOF with SAIL/Spike as reference model successfully ?
• Ran the new tests on RISCOF in coverage mode
• Link to Google-Drive folder containing the new coverage reports (See this for more info): < SPECIFY HERE >
• Link to PR in RISCV-ISAC from which the reports were generated : < SPECIFY HERE >
• Changelog entry created with a minor patch

Optional Checklist:

• RISCV-V CTG PR link if tests were generated using it : Add unratified Zicfiss extension riscv-software-src/riscv-ctg#94
• Were the tests hand-written/modified ?
• Have you run these on any hard DUT model ? Please specify name and provide link if possible in the description
• If you have modified arch_test.h Please provide a detailed description of the changes in the Description section above.