[vm] Remove obsolete kernel constant expression evaluator.

Change-Id: I16c515135468e526263db180f7252e7fdebe6414
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/111643
Commit-Queue: Aske Simon Christensen <askesc@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>

Author: askeksa

runtime/vm/compiler/compiler_sources.gni

@@ -107,8 +107,8 @@ compiler_sources = [
   "frontend/bytecode_reader.h",
   "frontend/bytecode_scope_builder.cc",
   "frontend/bytecode_scope_builder.h",
-  "frontend/constant_evaluator.cc",
-  "frontend/constant_evaluator.h",
+  "frontend/constant_reader.cc",
+  "frontend/constant_reader.h",
   "frontend/flow_graph_builder.cc",
   "frontend/flow_graph_builder.h",
   "frontend/kernel_binary_flowgraph.cc",