Revert "Rename -Zoom=panic to -Zoom=unwind"

This reverts commit 4b981c2648.

compiler/rustc_session/src/config.rs

@@ -3048,9 +3048,9 @@ pub(crate) mod dep_tracking {
 #[derive(Clone, Copy, PartialEq, Hash, Debug, Encodable, Decodable, HashStable_Generic)]
 pub enum OomStrategy {
     /// Generate a panic that can be caught by `catch_unwind`.
-    Unwind,
+    Panic,
 
-    /// Calls the panic hook as normal but aborts instead of unwinding.
+    /// Abort the process immediately.
     Abort,
 }
 
@@ -3059,7 +3059,7 @@ impl OomStrategy {
 
     pub fn should_panic(self) -> u8 {
         match self {
-            OomStrategy::Unwind => 1,
+            OomStrategy::Panic => 1,
             OomStrategy::Abort => 0,
         }
     }

compiler/rustc_session/src/options.rs

@@ -662,7 +662,7 @@ mod parse {
 
     pub(crate) fn parse_oom_strategy(slot: &mut OomStrategy, v: Option<&str>) -> bool {
         match v {
-            Some("unwind") => *slot = OomStrategy::Unwind,
+            Some("panic") => *slot = OomStrategy::Panic,
             Some("abort") => *slot = OomStrategy::Abort,
             _ => return false,
         }