Move default-field-values tests into a subdirectory

tests/ui/structs/default-field-values/failures.stderr

@@ -1,5 +1,5 @@
 error: the `#[default]` attribute may only be used on unit enum variants or variants where every field has a default value
-  --> $DIR/default-field-values-failures.rs:47:5
+  --> $DIR/failures.rs:47:5
    |
 LL |     Variant {}
    |     ^^^^^^^
@@ -7,7 +7,7 @@ LL |     Variant {}
    = help: consider a manual implementation of `Default`
 
 error: generic parameters may not be used in const operations
-  --> $DIR/default-field-values-failures.rs:22:23
+  --> $DIR/failures.rs:22:23
    |
 LL |     bat: i32 = <Qux<{ C }> as T>::K,
    |                       ^ cannot perform const operation using `C`
@@ -16,19 +16,19 @@ LL |     bat: i32 = <Qux<{ C }> as T>::K,
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: default fields are not supported in tuple structs
-  --> $DIR/default-field-values-failures.rs:26:22
+  --> $DIR/failures.rs:26:22
    |
 LL | pub struct Rak(i32 = 42);
    |                      ^^ default fields are only supported on structs
 
 error: generic `Self` types are currently not permitted in anonymous constants
-  --> $DIR/default-field-values-failures.rs:20:14
+  --> $DIR/failures.rs:20:14
    |
 LL |     bar: S = Self::S,
    |              ^^^^
 
 error[E0277]: the trait bound `S: Default` is not satisfied
-  --> $DIR/default-field-values-failures.rs:14:5
+  --> $DIR/failures.rs:14:5
    |
 LL | #[derive(Debug, Default)]
    |                 ------- in this derive macro expansion
@@ -44,13 +44,13 @@ LL | pub struct S;
    |
 
 error: missing mandatory field `bar`
-  --> $DIR/default-field-values-failures.rs:53:21
+  --> $DIR/failures.rs:53:21
    |
 LL |     let _ = Bar { .. };
    |                     ^
 
 error[E0308]: mismatched types
-  --> $DIR/default-field-values-failures.rs:57:17
+  --> $DIR/failures.rs:57:17
    |
 LL |     let _ = Rak(..);
    |             --- ^^ expected `i32`, found `RangeFull`
@@ -58,29 +58,29 @@ LL |     let _ = Rak(..);
    |             arguments to this struct are incorrect
    |
 note: tuple struct defined here
-  --> $DIR/default-field-values-failures.rs:26:12
+  --> $DIR/failures.rs:26:12
    |
 LL | pub struct Rak(i32 = 42);
    |            ^^^
 help: you might have meant to use `..` to skip providing a value for expected fields, but this is only supported on non-tuple struct literals; it is instead interpreted as a `std::ops::RangeFull` literal
-  --> $DIR/default-field-values-failures.rs:57:17
+  --> $DIR/failures.rs:57:17
    |
 LL |     let _ = Rak(..);
    |                 ^^
 
 error[E0061]: this struct takes 1 argument but 2 arguments were supplied
-  --> $DIR/default-field-values-failures.rs:59:13
+  --> $DIR/failures.rs:59:13
    |
 LL |     let _ = Rak(0, ..);
    |             ^^^    -- unexpected argument #2 of type `RangeFull`
    |
 help: you might have meant to use `..` to skip providing a value for expected fields, but this is only supported on non-tuple struct literals; it is instead interpreted as a `std::ops::RangeFull` literal
-  --> $DIR/default-field-values-failures.rs:59:20
+  --> $DIR/failures.rs:59:20
    |
 LL |     let _ = Rak(0, ..);
    |                    ^^
 note: tuple struct defined here
-  --> $DIR/default-field-values-failures.rs:26:12
+  --> $DIR/failures.rs:26:12
    |
 LL | pub struct Rak(i32 = 42);
    |            ^^^
@@ -91,18 +91,18 @@ LL +     let _ = Rak(0);
    |
 
 error[E0061]: this struct takes 1 argument but 2 arguments were supplied
-  --> $DIR/default-field-values-failures.rs:61:13
+  --> $DIR/failures.rs:61:13
    |
 LL |     let _ = Rak(.., 0);
    |             ^^^ -- unexpected argument #1 of type `RangeFull`
    |
 help: you might have meant to use `..` to skip providing a value for expected fields, but this is only supported on non-tuple struct literals; it is instead interpreted as a `std::ops::RangeFull` literal
-  --> $DIR/default-field-values-failures.rs:61:17
+  --> $DIR/failures.rs:61:17
    |
 LL |     let _ = Rak(.., 0);
    |                 ^^
 note: tuple struct defined here
-  --> $DIR/default-field-values-failures.rs:26:12
+  --> $DIR/failures.rs:26:12
    |
 LL | pub struct Rak(i32 = 42);
    |            ^^^

tests/ui/structs/default-field-values/invalid-const.stderr

@@ -1,13 +1,13 @@
 error[E0080]: evaluation of constant value failed
-  --> $DIR/default-field-values-invalid-const.rs:5:19
+  --> $DIR/invalid-const.rs:5:19
    |
 LL |     pub bax: u8 = panic!("asdf"),
-   |                   ^^^^^^^^^^^^^^ the evaluated program panicked at 'asdf', $DIR/default-field-values-invalid-const.rs:5:19
+   |                   ^^^^^^^^^^^^^^ the evaluated program panicked at 'asdf', $DIR/invalid-const.rs:5:19
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0080]: evaluation of `Baz::<C>::bat::{constant#0}` failed
-  --> $DIR/default-field-values-invalid-const.rs:11:19
+  --> $DIR/invalid-const.rs:11:19
    |
 LL |     pub bat: u8 = 130 + 130,
    |                   ^^^^^^^^^ attempt to compute `130_u8 + 130_u8`, which would overflow