Add Overflow check to DecodeAltNames input buffer access

[tatowicz]

Description

Add checks for issue found by OSS fuzz.

Fixes zd# #15333

Testing

Tested with provided reproduction code on ZD ticket #15333

Checklist

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

[dgarske]

8 bit, trailing spaces or tabs:
./wolfcrypt/src/asn.c:17367:        /* Verify idx can't overflow input buffer */
weird control chars, hard tabs, CRs, trailing whitespace:
./wolfcrypt/src/asn.c:17367:        /* Verify idx can't overflow input buffer */
warning, overlong lines added:
/wolfcrypt/src/asn.c:17414         else if (current_byte == (ASN_CONTEXT_SPECIFIC | ASN_CONSTRUCTED | ASN_DIR_TYPE)) {
/wolfcrypt/src/asn.c:17608         else if (current_byte == (ASN_CONTEXT_SPECIFIC | ASN_CONSTRUCTED | ASN_OTHER_TYPE))
    check-source-text fail_AB
exiting with status 1```