[wasm] Add regression test for issue 7914

I forgot to add this test to the previous CL:
https://crrev.com/c/1122409

R=ahaas@chromium.org

Bug: v8:7914
Change-Id: I4ed3bce37ce1e42a56eabc02647d8cf91e4492c9
Reviewed-on: https://chromium-review.googlesource.com/1124687
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54184}

test/mjsunit/regress/wasm/regress-7914.js

@@ -0,0 +1,18 @@
+// 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.
+
+load('test/mjsunit/wasm/wasm-constants.js');
+load('test/mjsunit/wasm/wasm-module-builder.js');
+
+const builder = new WasmModuleBuilder();
+builder.addMemory(16, 32, false);
+builder.addFunction('main', kSig_i_v)
+    .addBody([
+      ...wasmI32Const(10000),  // i32.const 10000
+      kExprGrowMemory, 0,      // grow_memory --> -1
+      kExprI32Popcnt,          // i32.popcnt  --> 32
+    ])
+    .exportFunc();
+const instance = builder.instantiate();
+assertEquals(32, instance.exports.main());