Move dead_code related tests to test/ui/dead-code

This helps organize the tests better.  I also renamed several of the tests to remove redundant dead-code in the path, and better match what they're testing

Author: Quantumplation

src/test/ui/dead-code-alias-in-pat.rs renamed to src/test/ui/lint/dead-code/alias-in-pat.rs

@@ -1,11 +1,11 @@
 error: function is never used: `foo`
-  --> $DIR/fail-no-dead-code.rs:4:1
+  --> $DIR/basic.rs:4:1
    |
 LL | fn foo() {
    | ^^^^^^^^
    |
 note: lint level defined here
-  --> $DIR/fail-no-dead-code.rs:1:9
+  --> $DIR/basic.rs:1:9
    |
 LL | #![deny(dead_code)]
    |         ^^^^^^^^^

src/test/ui/lint-dead-code-associated-type.rs renamed to src/test/ui/lint/dead-code/associated-type.rs

@@ -1,11 +1,11 @@
 error: enum is never used: `E`
-  --> $DIR/lint-dead-code-empty-unused-enum.rs:3:1
+  --> $DIR/empty-unused-enum.rs:3:1
    |
 LL | enum E {}
    | ^^^^^^
    |
 note: lint level defined here
-  --> $DIR/lint-dead-code-empty-unused-enum.rs:1:9
+  --> $DIR/empty-unused-enum.rs:1:9
    |
 LL | #![deny(unused)]
    |         ^^^^^^

src/test/ui/fail-no-dead-code.rs renamed to src/test/ui/lint/dead-code/basic.rs

@@ -1,11 +1,11 @@
 error: type alias is never used: `Unused`
-  --> $DIR/lint-dead-code-impl-trait.rs:12:1
+  --> $DIR/impl-trait.rs:12:1
    |
 LL | type Unused = ();
    | ^^^^^^^^^^^^^^^^^
    |
 note: lint level defined here
-  --> $DIR/lint-dead-code-impl-trait.rs:1:9
+  --> $DIR/impl-trait.rs:1:9
    |
 LL | #![deny(dead_code)]
    |         ^^^^^^^^^

src/test/ui/fail-no-dead-code.stderr renamed to src/test/ui/lint/dead-code/basic.stderr

@@ -1,11 +1,11 @@
 error: type alias is never used: `Unused`
-  --> $DIR/lint-dead-code-type-alias.rs:4:1
+  --> $DIR/type-alias.rs:4:1
    |
 LL | type Unused = u8;
    | ^^^^^^^^^^^^^^^^^
    |
 note: lint level defined here
-  --> $DIR/lint-dead-code-type-alias.rs:1:9
+  --> $DIR/type-alias.rs:1:9
    |
 LL | #![deny(dead_code)]
    |         ^^^^^^^^^

src/test/ui/dead-code-closure-bang.rs renamed to src/test/ui/lint/dead-code/closure-bang.rs

@@ -1,24 +1,24 @@
 error: struct is never constructed: `F`
-  --> $DIR/lint-dead-code-unused-enum.rs:3:1
+  --> $DIR/unused-enum.rs:3:1
    |
 LL | struct F;
    | ^^^^^^^^^
    |
 note: lint level defined here
-  --> $DIR/lint-dead-code-unused-enum.rs:1:9
+  --> $DIR/unused-enum.rs:1:9
    |
 LL | #![deny(unused)]
    |         ^^^^^^
    = note: `#[deny(dead_code)]` implied by `#[deny(unused)]`
 
 error: struct is never constructed: `B`
-  --> $DIR/lint-dead-code-unused-enum.rs:4:1
+  --> $DIR/unused-enum.rs:4:1
    |
 LL | struct B;
    | ^^^^^^^^^
 
 error: enum is never used: `E`
-  --> $DIR/lint-dead-code-unused-enum.rs:6:1
+  --> $DIR/unused-enum.rs:6:1
    |
 LL | enum E {
    | ^^^^^^

src/test/ui/lint/lint-dead-code-const-and-self.rs renamed to src/test/ui/lint/dead-code/const-and-self.rs

@@ -1,11 +1,11 @@
 error: variant is never constructed: `Bar`
-  --> $DIR/lint-dead-code-unused-variant.rs:8:5
+  --> $DIR/unused-struct-variant.rs:8:5
    |
 LL |     Bar(B),
    |     ^^^^^^
    |
 note: lint level defined here
-  --> $DIR/lint-dead-code-unused-variant.rs:1:9
+  --> $DIR/unused-struct-variant.rs:1:9
    |
 LL | #![deny(unused)]
    |         ^^^^^^

src/test/ui/lint/lint-dead-code-empty-unused-enum.rs renamed to src/test/ui/lint/dead-code/empty-unused-enum.rs

@@ -1,11 +1,11 @@
 error: variant is never constructed: `Variant1`
-  --> $DIR/lint-dead-code-variant.rs:5:5
+  --> $DIR/unused-variant.rs:5:5
    |
 LL |     Variant1,
    |     ^^^^^^^^
    |
 note: lint level defined here
-  --> $DIR/lint-dead-code-variant.rs:1:9
+  --> $DIR/unused-variant.rs:1:9
    |
 LL | #![deny(dead_code)]
    |         ^^^^^^^^^

src/test/ui/lint/lint-dead-code-empty-unused-enum.stderr renamed to src/test/ui/lint/dead-code/empty-unused-enum.stderr

@@ -1,11 +1,11 @@
 error: function is never used: `foo`
-  --> $DIR/fail-no-dead-code-core.rs:7:1
+  --> $DIR/with-core-crate.rs:7:1
    |
 LL | fn foo() {
    | ^^^^^^^^
    |
 note: lint level defined here
-  --> $DIR/fail-no-dead-code-core.rs:1:9
+  --> $DIR/with-core-crate.rs:1:9
    |
 LL | #![deny(dead_code)]
    |         ^^^^^^^^^