AES: Improve CFB and OFB and add tests

[SparkiDev]

Description

Improve performance of CFB and OFB.
Only have one implementation that is used by OFB encrypt and decrypt.

Update AES testing in unit.test.

Update benchmarking of CFB and OFb to include decrypt.

Testing

Regression tested AES.

Checklist

• added tests
• updated/added doxygen
• updated appropriate READMEs
• Updated manual and documentation

[devin-ai-integration]

🛟 Devin Lifeguard found 2 likely issues in this PR

• limit-stack-usage snippet: Convert the large local buffers (e.g. plain/cipher/decrypted in test_wc_AesEcbEncryptDecrypt_WithKey) to heap allocations guarded by WOLFSSL_SMALL_STACK (malloc/free) or reuse a single static buffer to keep per-function stack usage under 100 bytes.
• limit-stack-usage snippet: Apply the WOLFSSL_SMALL_STACK pattern in the test functions (e.g. allocate plain, cipher, and decrypted with XMALLOC/XFREE instead of fixed-size local arrays) so each stack frame uses well under 100 bytes.

@SparkiDev
please take a look at the above issues which Devin flagged. Devin will not fix these issues automatically.

[SparkiDev]

Small stack respected in new test_aes.c code.

[dgarske]

I resolved the merge conflict and approve.

[JacobBarthelmeh]

Nice improvements! I have a minor concern about pervious ports working with the additional sanity check though.

[SparkiDev]

Removed check and removed tests for NULL.
Rebased.