[vm] Remove assert in ArgumentsDescriptor::Write

The property that it was checking does not hold after
commit 5e77a23
which brought argument descriptors from vm-isolate
into normal isolate.

However the code does not actually rely on this property
anywhere so assert can be simply removed.

Fixes #61041

TEST=ci

Change-Id: I500d39ce473948a11a5a743b0241ab54cc040966
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/438680
Commit-Queue: Slava Egorov <[email protected]>
Reviewed-by: Martin Kustermann <[email protected]>

Author: mraleph

runtime/vm/compiler/backend/il_serializer.cc

@@ -109,7 +109,6 @@ void ArgumentsDescriptor::Write(FlowGraphSerializer* s) const {
     s->Write<intptr_t>(Count());
   } else {
     ASSERT(array_.IsCanonical());
-    ASSERT(!array_.InVMIsolateHeap());
     s->Write<intptr_t>(-1);
     s->Write<const Array&>(array_);
   }