Revert "Move va_arg files to cpp"

This reverts commit e17ef73.

Author: lucic71

tests/unit/out/unsafe/va_arg_concat.rs

@@ -10,7 +10,7 @@ pub unsafe fn sum_ints_0(mut first: i32, args: &[VaArg]) -> i32 {
     let mut ap: VaList = VaList::default();
     let mut total: i32 = first;
     ap = VaList::new(args);
-    let mut val: i32 = 0_i32;
+    let mut val: i32 = <i32>::default();
     'loop_: while ((({
         val = ap.arg::<i32>();
         val

tests/unit/out/unsafe/va_arg_snprintf.rs

@@ -24,7 +24,7 @@ pub fn main() {
     }
 }
 unsafe fn main_0() -> i32 {
-    let mut buf: [u8; 64] = [0_u8; 64];
+    let mut buf: [u8; 64] = [<u8>::default(); 64];
     assert!(
         ((unsafe {
             let _buf: *mut u8 = buf.as_mut_ptr();

tests/unit/out/unsafe/va_arg_two_passes.rs

@@ -11,7 +11,7 @@ pub unsafe fn sum_then_product_0(mut first: i32, args: &[VaArg]) -> i32 {
     let mut sum: i32 = first;
     let mut product: i32 = first;
     ap = VaList::new(args);
-    let mut val: i32 = 0_i32;
+    let mut val: i32 = <i32>::default();
     'loop_: while ((({
         val = ap.arg::<i32>();
         val

tests/unit/va_arg_chain.cpp tests/unit/va_arg_chain.ctests/unit/va_arg_chain.cpp renamed to tests/unit/va_arg_chain.c

@@ -8,7 +8,9 @@ int extract_nth(int n, va_list ap) {
   return va_arg(ap, int);
 }
 
-int middle_layer(int n, va_list ap) { return extract_nth(n, ap); }
+int middle_layer(int n, va_list ap) {
+  return extract_nth(n, ap);
+}
 
 int top_level(int n, ...) {
   va_list ap;