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_delete.any.js.ini

@@ -1,16 +1,13 @@
 [idbobjectstore_delete.any.worker.html]
-  expected: CRASH
+  expected: TIMEOUT
   [delete() removes record (inline keys)]
-    expected: FAIL
-
-  [delete() key doesn't match any records]
-    expected: FAIL
+    expected: TIMEOUT
 
   [Object store's key path is an object attribute]
-    expected: FAIL
+    expected: TIMEOUT
 
   [delete() removes record (out-of-line keys)]
-    expected: FAIL
+    expected: TIMEOUT
 
   [delete() removes all of the records in the range]
     expected: FAIL
@@ -23,18 +20,15 @@
   expected: ERROR
 
 [idbobjectstore_delete.any.html]
-  expected: CRASH
+  expected: TIMEOUT
   [delete() removes record (inline keys)]
-    expected: FAIL
-
-  [delete() key doesn't match any records]
-    expected: FAIL
+    expected: TIMEOUT
 
   [Object store's key path is an object attribute]
-    expected: FAIL
+    expected: TIMEOUT
 
   [delete() removes record (out-of-line keys)]
-    expected: FAIL
+    expected: TIMEOUT
 
   [delete() removes all of the records in the range]
     expected: FAIL