Adding wmemcheck hooks for SIMD loads and stores

#### Feature

Adding hooks to track SIMD loads and stores for wmemcheck, similary to.

#### Benefit

Wmemcheck is more thorough in its read/write error detection if SIMD loads/stores are tracked.

#### Implementation

Hooks added would be similar to existing `before_load()` and `before_store()` hooks defined in `func_environ.rs`.

#### Alternatives

N/A