Rollup merge of #157627 - folkertdev:remove-llvm-va_end, r=RalfJung

remove LLVM `va_end` calls

tracking issue: rust-lang/rust#44930

The operation is a no-op, so we skip it.

Author: jhpratt

src/intrinsic/mod.rs

@@ -705,10 +705,6 @@ impl<'a, 'gcc, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tc
         unimplemented!();
     }
 
-    fn va_end(&mut self, _va_list: RValue<'gcc>) {
-        // FIXME(antoyo): implement.
-    }
-
     fn retag_reg(&mut self, _ptr: Self::Value, _info: &RetagInfo<Self::Value>) -> Self::Value {
         unimplemented!()
     }