[WebAssembly] Add -m:e to the target triple.

This enables ELF-style name mangling, which primarily means using ".L" for
private symbols.

llvm-svn: 257020
diff --git a/llvm/test/CodeGen/WebAssembly/memory-addr64.ll b/llvm/test/CodeGen/WebAssembly/memory-addr64.ll
index 5de1f2b..d504c27 100644
--- a/llvm/test/CodeGen/WebAssembly/memory-addr64.ll
+++ b/llvm/test/CodeGen/WebAssembly/memory-addr64.ll
@@ -2,7 +2,7 @@
 
 ; Test that basic memory operations assemble as expected with 64-bit addresses.
 
-target datalayout = "e-p:64:64-i64:64-n32:64-S128"
+target datalayout = "e-m:e-p:64:64-i64:64-n32:64-S128"
 target triple = "wasm64-unknown-unknown"
 
 declare i64 @llvm.wasm.memory.size.i64() nounwind readonly