Fix clippy::unnecessary_map_or warning

```
warning: this `map_or` can be simplified
  --> tests/no-core/build.rs:15:5
   |
15 | /     env::var_os("RUSTC")
16 | |         .and_then(|rustc| Command::new(rustc).arg("--version").output().ok())
17 | |         .and_then(|output| String::from_utf8(output.stdout).ok())
18 | |         .map_or(false, |version| version.contains("nightly") || version.contains("dev"))
   | |________________________________________________________________________________________^
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_map_or
   = note: `-W clippy::unnecessary-map-or` implied by `-W clippy::all`
   = help: to override `-W clippy::all` add `#[allow(clippy::unnecessary_map_or)]`
help: use `is_some_and` instead
   |
18 -         .map_or(false, |version| version.contains("nightly") || version.contains("dev"))
18 +         .is_some_and(|version| version.contains("nightly") || version.contains("dev"))
   |

warning: this `map_or` can be simplified
   --> pin-project-internal/src/pinned_drop.rs:143:28
    |
143 |                         && get_ty_path(elem).map_or(false, |path| path.is_ident("Self"))
    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_map_or
    = note: `-W clippy::unnecessary-map-or` implied by `-W clippy::all`
    = help: to override `-W clippy::all` add `#[allow(clippy::unnecessary_map_or)]`
help: use `is_some_and` instead
    |
143 -                         && get_ty_path(elem).map_or(false, |path| path.is_ident("Self"))
143 +                         && get_ty_path(elem).is_some_and(|path| path.is_ident("Self"))
    |
```

Author: taiki-e

pin-project-internal/src/pinned_drop.rs

@@ -140,7 +140,7 @@ fn validate_sig(sig: &Signature) -> Result<()> {
                     // (mut) self: (<path>::)Pin<&mut Self>
                     if args.args.len() == 1
                         && ty.ident == "Pin"
-                        && get_ty_path(elem).map_or(false, |path| path.is_ident("Self"))
+                        && get_ty_path(elem).is_some_and(|path| path.is_ident("Self"))
                     {
                         if sig.unsafety.is_some() {
                             bail!(sig.unsafety, "implementing the method `drop` is not unsafe");

tests/no-core/build.rs

@@ -15,5 +15,5 @@ fn is_nightly() -> bool {
     env::var_os("RUSTC")
         .and_then(|rustc| Command::new(rustc).arg("--version").output().ok())
         .and_then(|output| String::from_utf8(output.stdout).ok())
-        .map_or(false, |version| version.contains("nightly") || version.contains("dev"))
+        .is_some_and(|version| version.contains("nightly") || version.contains("dev"))
 }