Add a Lint for Pointer to Integer Transmutes in Consts

compiler/rustc_mir_transform/src/errors.rs

@@ -121,3 +121,10 @@ pub(crate) struct MustNotSuspendReason {
     pub span: Span,
     pub reason: String,
 }
+
+#[derive(LintDiagnostic)]
+#[diag(mir_transform_undefined_transmute)]
+#[note]
+#[note(mir_transform_note2)]
+#[help]
+pub(crate) struct UndefinedTransmute;