Revert "[WebAssembly] Fixup `main` signature by default"

This reverts rL345880.  It caused some test failures on the
webassembly waterfall.  e.g. binaryen2.test_mainenv fails due
the fact that `envp` ends up being undef rather than 0.

Differential Revision: https://reviews.llvm.org/D54117

llvm-svn: 346187
diff --git a/llvm/test/CodeGen/WebAssembly/function-bitcasts.ll b/llvm/test/CodeGen/WebAssembly/function-bitcasts.ll
index 0853549..0e7fcd5 100644
--- a/llvm/test/CodeGen/WebAssembly/function-bitcasts.ll
+++ b/llvm/test/CodeGen/WebAssembly/function-bitcasts.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -asm-verbose=false -wasm-disable-explicit-locals -wasm-keep-registers -enable-emscripten-cxx-exceptions | FileCheck %s
+; RUN: llc < %s -asm-verbose=false -wasm-disable-explicit-locals -wasm-keep-registers -enable-emscripten-cxx-exceptions -wasm-temporary-workarounds=false | FileCheck %s
 
 ; Test that function pointer casts are replaced with wrappers.