Revert "[d8][wasm] Test wasm compilation completion"

This reverts commit ed2605f0.

Reason for revert: Test flakes.

Original change's description:
> [d8][wasm] Test wasm compilation completion
> 
> d8 was recently changed to keep running until wasm compilation has
> completed. This adds a message test to test that.
> 
> R=​ahaas@chromium.org
> 
> Change-Id: I73af53b6df4ee5f9a6afd26cf2d71a269140465f
> Reviewed-on: https://chromium-review.googlesource.com/966184
> Reviewed-by: Andreas Haas <ahaas@chromium.org>
> Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#52008}

TBR=ahaas@chromium.org,clemensh@chromium.org

Change-Id: If1e015bd346a71df1da8effe92882c37a00d1e62
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/968521Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52023}

test/message/wasm-finish-compilation.js

-// Copyright 2018 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// Flags: --no-stress-opt
-
-load('test/mjsunit/wasm/wasm-constants.js');
-load('test/mjsunit/wasm/wasm-module-builder.js');
-
-// Test that d8 does not terminate until wasm compilation has finished and the
-// promise was resolved.
-
-var builder = new WasmModuleBuilder();
-// Add a few functions so it takes some time to compile.
-for (var i = 0; i < 2000; ++i) {
-  builder.addFunction('fun' + i, kSig_i_v)
-      .addBody([...wasmI32Const(i)])
-      .exportFunc();
-}
-builder.asyncInstantiate()
-    .then(({module, instance}) => instance.exports.fun1155())
-    .then(res => print('Result of executing fun1155: ' + res));

test/message/wasm-finish-compilation.out

-Result of executing fun1155: 1155

test/mjsunit/wasm/wasm-module-builder.js

@@ -683,10 +683,6 @@ class WasmModuleBuilder {
     return instance;
   }
 
-  asyncInstantiate(ffi) {
-    return WebAssembly.instantiate(this.toBuffer(), ffi);
-  }
-
   toModule(debug = false) {
     return new WebAssembly.Module(this.toBuffer(debug));
   }