Return error if Transaction contains writable executable or ProgramData accounts (#19629)

* Return error if Transaction locks an executable as writable

* Return error if a ProgramData account is writable but the upgradable loader isn't present

* Remove unreachable clause

* Fixup bpf tests

* Review comments

* Add new TransactionError

* Disallow writes to any upgradeable-loader account when loader not present; remove is_upgradeable_loader_present exception for all other executables

sdk/src/transaction/mod.rs

@@ -119,6 +119,10 @@ pub enum TransactionError {
     /// Transaction version is unsupported
     #[error("Transaction version is unsupported")]
     UnsupportedVersion,
+
+    /// Transaction loads a writable account that cannot be written
+    #[error("Transaction loads a writable account that cannot be written")]
+    InvalidWritableAccount,
 }
 
 pub type Result<T> = result::Result<T, TransactionError>;