R=titzer@chromium.org
TEST=unittests/WasmModuleVerifyTest.DataSegmentWithImmutableGlobal, unittests/WasmModuleVerifyTest.DataSegmentWithMutableImportedGlobal, unittests/WasmModuleVerifyTest.DataSegmentWithImmutableImportedGlobal

Review-Url: https://codereview.chromium.org/2493433002
Cr-Commit-Position: refs/heads/master@{#40865}