[CoreCLR] Remove DSO-cache hashes: decouple JNI preload and rework p/invoke fallback

## Context

After #12010 (p/invoke override rewritten to plain string comparisons) and #12033 (dlopen-based assembly store loading, which removes `DSOApkEntry` and the ZIP-scan fast path), the **only** remaining functional consumer of `DSOCacheEntry.hash` in the CoreCLR host is the p/invoke fallback lookup (`MonodroidDl::find_dso_cache_entry`, called once from `monodroid_dlopen(name)`).

JNI shared-library preloading (`host.cc`) uses the `dso_cache` array too, but it needs **no** hashes: it is driven by `dso_jni_preloads_idx` (a list of indexes) → `DSOCacheEntry::name_index` → name → `System.loadLibrary`. `entry.hash` appears there only as a `log_debug` argument, and `entry.real_name_hash` is only used by `find_dso_apk_entry`, which #12033 deletes.

In other words, preload and "resolve an arbitrary p/invoke library by name" are two unrelated concerns fused into one hash-indexed table; the hashes exist solely for the fallback lookup.

## Blocked on

- #12010
- #12033

Both actively rewrite the same files (`precompiled.cc`, `pinvoke-override*.hh`, `monodroid-dl.hh`, the CLR app-config generator), so this cleanup should land on a stable base to avoid churn/conflicts.

## Work

1. **Decouple JNI preload** into a standalone, hash-free list of names (generator side in `ApplicationConfigNativeAssemblyGeneratorCLR.cs` + the preload loop in `host.cc`). No dependency on `DSOCacheEntry` hash fields.
- Note on handle sharing: today preload writes the loaded handle back into `dso_cache` (+ alias entries) so a later p/invoke reuses it. If decoupled, a preloaded lib later hit by p/invoke simply re-resolves via `System.loadLibrary` (idempotent → same handle, negligible cost). Correctness is preserved.
2. **Rework/remove the p/invoke fallback lookup** (`monodroid_dlopen(name)` → `find_dso_cache_entry`), aligned with the #12010 direction of letting CoreCLR's own resolver / `System.loadLibrary` handle arbitrary libraries.
3. Once (1) and (2) are done, `dso_cache` collapses to just preload names → **drop `DSOCacheEntry.hash` / `real_name_hash` and remove CRC32 from the CoreCLR DSO path entirely.**

## Out of scope / note

#12013 ("[CoreCLR] Replace xxhash with crc32") deliberately only does the mechanical xxHash→CRC32 swap on the surviving fallback lookup. It does **not** attempt the decoupling or fallback rework above.

Wait for #12010 and #12033, then read ApplicationConfigNativeAssemblyGeneratorCLR.cs and the preload loop in host.cc, followed by the fallback paths in precompiled.cc, pinvoke-override*.hh, and monodroid-dl.hh. Trace how preload names and p/invoke resolution currently use dso_cache; the work is done when preload no longer depends on hash fields, fallback lookup is reworked, and hash/CRC32 code is removed from this path.

Written by the indexing model from the issue text.