Revert r252858: "[WebAssembly] Switch to MC for instruction printing."

It broke the CMake build:

"Cannot find source file: WebAssemblyRegNumbering.cpp"

llvm-svn: 252897
diff --git a/llvm/test/CodeGen/WebAssembly/unreachable.ll b/llvm/test/CodeGen/WebAssembly/unreachable.ll
index e14c588..a16e452 100644
--- a/llvm/test/CodeGen/WebAssembly/unreachable.ll
+++ b/llvm/test/CodeGen/WebAssembly/unreachable.ll
@@ -12,7 +12,7 @@
 declare void @abort()
 
 ; CHECK-LABEL: f1:
-; CHECK: call abort
+; CHECK: call $abort
 ; CHECK: unreachable
 define i32 @f1() {
   call void @abort()