Upgrade Emscripten targets to use upstream LLVM backend

 - Refactors the Emscripten target spec to share code with other wasm
   targets.
 - Replaces the incorrect wasm32 C call ABI with the old asmjs
   version, which is correct for both wasm32 and JS.
 - Updates the varargs ABI used by Emscripten and deletes the old one.
 - Removes the obsolete wasm32-experimental-emscripten target.
 - Temporarily makes Emscripten targets use panic=abort by default
   because supporting unwinding will require an LLVM patch.

2 files changed, 2 insertions, 1 deletions

diff --git a/src/test/ui/binding/fn-arg-incomplete-pattern-drop-order.rs b/src/test/ui/binding/fn-arg-incomplete-pattern-drop-order.rs
index ea4a9e5afa5..4e0a238c5d4 100644
--- a/src/test/ui/binding/fn-arg-incomplete-pattern-drop-order.rs
+++ b/src/test/ui/binding/fn-arg-incomplete-pattern-drop-order.rs
@@ -2,7 +2,7 @@
 // Check that partially moved from function parameters are dropped after the
 // named bindings that move from them.
 
-// ignore-wasm32-bare compiled with panic=abort by default
+// ignore-emscripten compiled with panic=abort by default
 
 use std::{panic, cell::RefCell};
 
diff --git a/src/test/ui/binding/match-arm-statics.rs b/src/test/ui/binding/match-arm-statics.rs
index 5f7e357eeb2..e6d17def147 100644
--- a/src/test/ui/binding/match-arm-statics.rs
+++ b/src/test/ui/binding/match-arm-statics.rs
@@ -1,6 +1,7 @@
 // run-pass
 #![allow(dead_code)]
 // compile-flags: -g
+// ignore-asmjs wasm2js does not support source maps yet
 
 #[derive(PartialEq, Eq)]
 struct NewBool(bool);