Fix reserved byte identifiers in the new streaming workload cases

[LunaStev]

Two cases introduced in #520 use the reserved type token byte as an ordinary identifier: a local in shared/test114.wave:32 and a function parameter in macos/arm64/test6.wave:34. The lexer emits TypeByte, so both fail parsing before their algorithms or OS operations can be exercised.

Linux case CI stops while checking the macOS file; Windows ARM64 case CI separately reports the shared case failure. These are observed remote CI failures, not target-specific language differences.

Source evidence at the head of #520:

• tests/cases/shared/test114.wave:32 — var byte: u8
• tests/cases/macos/arm64/test6.wave:34 — fun consume
• front/lexer/src/ident.rs:268 — "byte" => Token

Acceptance:

• Rename only the local/parameter and their references to an ordinary descriptive identifier.
• Preserve both algorithms, checks and platform placement; do not delete/skip the tests or weaken keyword recognition.
• Verify both source files parse, then run the shared workload and the native macOS kqueue workload on their supported runners.
• Keep legitimate byte type uses such as shared/test61.wave intact.

Related: Draft PR #520. #436 concerns the separate computed-index limitation exposed by the LoongArch workload.

Audit status: reproduced by the linked remote PR CI at commit 2ae0a91; no additional local build or execution was run during this audit.