Rollup merge of #151771 - hoodmane:wasm-double-panic, r=bjorn3

Fix: On wasm targets, call `panic_in_cleanup` if panic occurs in cleanup

Previously this was not correctly implemented. Each funclet may need its own terminate block, so this changes the `terminate_block` into a `terminate_blocks` `IndexVec` which can have a terminate_block for each funclet. We key on the first basic block of the funclet -- in particular, this is the start block for the old case of the top level terminate function.

I also fixed the `terminate` handler to not be invoked when a foreign exception is raised, mimicking the behavior from msvc. On wasm, in order to avoid generating a `catch_all` we need to call `llvm.wasm.get.exception` and `llvm.wasm.get.ehselector`.

Author: jhpratt

src/builder.rs

@@ -1655,6 +1655,10 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
         unimplemented!();
     }
 
+    fn get_funclet_cleanuppad(&self, _funclet: &Funclet) -> RValue<'gcc> {
+        unimplemented!();
+    }
+
     // Atomic Operations
     fn atomic_cmpxchg(
         &mut self,