Revert of [wasm] Enforce that function bodies end with the \"end\" opcode. (patchset #1 id:1 of https://codereview.chromium.org/2628203003/ )

Reason for revert:
OK, the failure really does seem to be due to this patch: It triggers Clang to crash

FAILED: obj/test/unittests/unittests/function-body-decoder-unittest.obj
E:\b\build\slave\cache\cipd\goma/gomacc.exe ../../third_party/llvm-build/Release+Asserts/bin/clang-cl.exe /nologo /showIncludes /FC @obj/test/unittests/unittests/function-body-decoder-unittest.obj.rsp /c ../../test/unittests/wasm/function-body-decoder-unittest.cc /Foobj/test/unittests/unittests/function-body-decoder-unittest.obj /Fd"obj/test/unittests/unittests_cc.pdb"
Assertion failed: (NumGaps == 0 || Bias < MaxDefRange) && "large ranges should not have gaps", file E:\b\build\slave\win_upload_clang\build\src\third_party\llvm\lib\MC\MCCodeView.cpp, line 531
Wrote crash dump file "C:\Users\CHROME~2\AppData\Local\Temp\goma_temp.5068\clang-cl.exe-563144.dmp"

Let's leave it out for now.

Original issue's description:
> Reland of [wasm] Enforce that function bodies end with the \"end\" opcode. (patchset #1 id:1 of https://codereview.chromium.org/2628883006/ )
>
> Reason for revert:
> Try a reland; this might not have been the source of tree-closing.
>
> Original issue's description:
> > Revert of [wasm] Enforce that function bodies end with the \"end\" opcode. (patchset #3 id:40001 of https://codereview.chromium.org/2630553002/ )
> >
> > Reason for revert:
> > Caused tree to close by failing compilation:
> >
> > https://build.chromium.org/p/client.v8/builders/V8%20Win64%20-%20clang/builds/4451
> >
> > Original issue's description:
> > > [wasm] Enforce that function bodies end with the \"end\" opcode.
> > >
> > > R=rossberg@chromium.org
> > > BUG=chromium:575167
> > >
> > > Review-Url: https://codereview.chromium.org/2630553002
> > > Cr-Commit-Position: refs/heads/master@{#42286}
> > > Committed: https://chromium.googlesource.com/v8/v8/+/fcc6e85ec6b01e5367795f98aff104b1ff23f619
> >
> > TBR=mtrofin@chromium.org,rossberg@chromium.org,jbroman@chromium.org,titzer@chromium.org
> > # Skipping CQ checks because original CL landed less than 1 days ago.
> > NOPRESUBMIT=true
> > NOTREECHECKS=true
> > NOTRY=true
> > BUG=chromium:575167
> >
> > Review-Url: https://codereview.chromium.org/2628883006
> > Cr-Commit-Position: refs/heads/master@{#42287}
> > Committed: https://chromium.googlesource.com/v8/v8/+/1d32a3989bc474745eeb618ebf094634f4efbb36
>
> TBR=mtrofin@chromium.org,rossberg@chromium.org,jbroman@chromium.org,titzer@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=chromium:575167
>
> Review-Url: https://codereview.chromium.org/2628203003
> Cr-Commit-Position: refs/heads/master@{#42296}
> Committed: https://chromium.googlesource.com/v8/v8/+/e539bd8e0eb6afc8e7c98c38584928d6bc799b5b

TBR=mtrofin@chromium.org,rossberg@chromium.org,jbroman@chromium.org,titzer@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:575167

Review-Url: https://codereview.chromium.org/2633583002
Cr-Commit-Position: refs/heads/master@{#42298}