[WebAssembly] Emit .param, .result, and .local through MC.

This eliminates one of the main remaining uses of EmitRawText.

llvm-svn: 253878
diff --git a/llvm/test/CodeGen/WebAssembly/comparisons_i64.ll b/llvm/test/CodeGen/WebAssembly/comparisons_i64.ll
index ba56f3f..0b0a873 100644
--- a/llvm/test/CodeGen/WebAssembly/comparisons_i64.ll
+++ b/llvm/test/CodeGen/WebAssembly/comparisons_i64.ll
@@ -6,8 +6,7 @@
 target triple = "wasm32-unknown-unknown"
 
 ; CHECK-LABEL: eq_i64:
-; CHECK-NEXT: .param i64{{$}}
-; CHECK-NEXT: .param i64{{$}}
+; CHECK-NEXT: .param i64, i64{{$}}
 ; CHECK-NEXT: .result i32{{$}}
 ; CHECK-NEXT: i64.eq $push[[NUM:[0-9]+]], $0, $1{{$}}
 ; CHECK-NEXT: return $pop[[NUM]]{{$}}