Add test for simplify-try misoptimization

Author: wesleywiser

src/test/mir-opt/issue-73223.rs

@@ -0,0 +1,13 @@
+fn main() {
+    let split = match Some(1) {
+        Some(v) => v,
+        None => return,
+    };
+
+    let _prev = Some(split);
+    assert_eq!(split, 1);
+}
+
+// EMIT_MIR_FOR_EACH_BIT_WIDTH
+// EMIT_MIR rustc.main.SimplifyArmIdentity.diff
+// EMIT_MIR rustc.main.PreCodegen.diff