[WebAssembly] Rename except_ref type to exnref

Summary:
We agreed to rename `except_ref` to `exnref` for consistency with other
reference types in
https://github.com/WebAssembly/exception-handling/issues/79. This also
renames WebAssemblyInstrExceptRef.td to WebAssemblyInstrRef.td in order
to use the file for other reference types in future.

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, hiraditya, sunfish, jfb, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64703

llvm-svn: 366145
diff --git a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyInstPrinter.cpp b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyInstPrinter.cpp
index cfa808b..a439b72 100644
--- a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyInstPrinter.cpp
+++ b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyInstPrinter.cpp
@@ -282,8 +282,8 @@
     return "funcref";
   case wasm::WASM_TYPE_FUNC:
     return "func";
-  case wasm::WASM_TYPE_EXCEPT_REF:
-    return "except_ref";
+  case wasm::WASM_TYPE_EXNREF:
+    return "exnref";
   case wasm::WASM_TYPE_NORESULT:
     return "void";
   default: