[WebAssembly] Rename relocations from R_WEBASSEMBLY_ to R_WASM_

See https://github.com/WebAssembly/tool-conventions/pull/95.

This is less typing and IMHO more readable, and it also fits with
our naming around the binary format which tends to use the short name.
e.g.

include/llvm/BinaryFormat/Wasm.h
tools/llvm-objdump/WasmDump.cpp
etc..

Differential Revision: https://reviews.llvm.org/D57611

llvm-svn: 353062
diff --git a/llvm/tools/llvm-objdump/WasmDump.cpp b/llvm/tools/llvm-objdump/WasmDump.cpp
index 988aa80..1c805ba 100644
--- a/llvm/tools/llvm-objdump/WasmDump.cpp
+++ b/llvm/tools/llvm-objdump/WasmDump.cpp
@@ -36,7 +36,7 @@
   raw_string_ostream Fmt(FmtBuf);
   if (SI == Obj->symbol_end()) {
     // Not all wasm relocations have symbols associated with them.
-    // In particular R_WEBASSEMBLY_TYPE_INDEX_LEB.
+    // In particular R_WASM_TYPE_INDEX_LEB.
     Fmt << Rel.Index;
   } else {
     Expected<StringRef> SymNameOrErr = SI->getName();