Implement a basic WASM API using wasmer.

Currently this only supports functions that take and return numeric
types. Byte arrays, and callbacks will come later, in a separate
wrapper package.

Bug: #37882
Change-Id: I7bb82be83cbbb6062736b3e958f89d021f1af4bb
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/114586
Commit-Queue: Liam Appelbe <[email protected]>
Reviewed-by: Samir Jindel <[email protected]>
Reviewed-by: Ryan Macnak <[email protected]>

Author: liamappelbe

runtime/BUILD.gn

@@ -240,6 +240,10 @@ library_for_all_configs("libdart") {
     "third_party/double-conversion/src:libdouble_conversion",
     ":generate_version_cc_file",
   ]
+  if (dart_enable_wasm) {
+    extra_deps += [ "//third_party/wasmer" ]
+    defines = [ "DART_ENABLE_WASM" ]
+  }
   if (is_fuchsia) {
     if (using_fuchsia_sdk) {
       extra_deps += [ "$fuchsia_sdk_root/pkg:fdio" ]