Switch indexeddb backend to sqlite and improve IPC messaging (#38187)

- Use sqlite instead of heed. (one indexed database = one sqlite
database)
- Implement the backend for indexes
- Use keyranges where needed (as specified by the spec)
- Implement `getKey`
- Fix channel error messaging (led to a bunch of changes to how async
requests are handled)

Note: `components/net/indexeddb/engines/sqlite/serialize.rs` is unused;
I can delete it if needed.

Testing: Switching to sqlite eliminated many panics (exposing some new
failures).
Fixes: #38040

---------

Signed-off-by: Ashwin Naren <arihant2math@gmail.com>

tests/wpt/meta/IndexedDB/idbobjectstore_clear.any.js.ini

@@ -1,5 +1,13 @@
 [idbobjectstore_clear.any.html]
-  expected: CRASH
+  [Verify clear removes all records ]
+    expected: FAIL
+
+  [Clear removes all records from an index ]
+    expected: FAIL
+
+  [If the object store has been deleted, the implementation must throw a DOMException of type InvalidStateError ]
+    expected: FAIL
+
 
 [idbobjectstore_clear.any.sharedworker.html]
   expected: ERROR
@@ -8,4 +16,11 @@
   expected: ERROR
 
 [idbobjectstore_clear.any.worker.html]
-  expected: CRASH
+  [Verify clear removes all records ]
+    expected: FAIL
+
+  [Clear removes all records from an index ]
+    expected: FAIL
+
+  [If the object store has been deleted, the implementation must throw a DOMException of type InvalidStateError ]
+    expected: FAIL