[WebAssembly] Switch to *-wasm as the default target triple.

This makes wasm32-unknown-unknown-wasm the default, which supports
the .o file writer and the new linking ABI. To enable s2wasm-compatible
output, use the wasm32-unknown-unknown-elf triple.

llvm-svn: 323220
diff --git a/llvm/test/CodeGen/WebAssembly/dbgvalue.ll b/llvm/test/CodeGen/WebAssembly/dbgvalue.ll
index 438bea3..088fc8f 100644
--- a/llvm/test/CodeGen/WebAssembly/dbgvalue.ll
+++ b/llvm/test/CodeGen/WebAssembly/dbgvalue.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -O0 -verify-machineinstrs -mtriple=wasm32-unknown-unknown-wasm | FileCheck %s
+; RUN: llc < %s -O0 -verify-machineinstrs | FileCheck %s
 
 ; CHECK: %bb.0
 ; CHECK: #DEBUG_VALUE: usage:self <- %4