audit code base for failpoints that should be pausable_failpoint!

Methodology:
1. search for `"pause"` and fix as appropriate
2. search for `=pause` => no further fixes found

Future work: audit all uses of fail::fail_point! / auto-convert them all
to use pausable_failpoint! (or implement our own failpoints library)

pageserver/src/control_plane_client.rs

@@ -210,7 +210,7 @@ impl ControlPlaneGenerationsApi for ControlPlaneClient {
                 .collect(),
         };
 
-        fail::fail_point!("control-plane-client-validate");
+        crate::tenant::pausable_failpoint!("control-plane-client-validate");
 
         let response: ValidateResponse = self.retry_http_forever(&re_attach_path, request).await?;
 

pageserver/src/tenant.rs

@@ -144,6 +144,7 @@ macro_rules! pausable_failpoint {
         }
     };
 }
+pub(crate) use pausable_failpoint;
 
 pub mod blob_io;
 pub mod block_io;