[CIR][CIRGen][Exception] Workaround internal testcase break

Recent work on exceptions broke an internal testcase, free the path
back while I work on a holistic solution.

clang/lib/CIR/CodeGen/CIRGenException.cpp

@@ -271,8 +271,6 @@ mlir::LogicalResult CIRGenFunction::buildCXXTryStmt(const CXXTryStmt &S) {
       });
 
   enterCXXTryStmt(S, catchOp);
-  llvm_unreachable("NYI");
-
   if (buildStmt(S.getTryBlock(), /*useCurrentScope=*/true).failed())
     return mlir::failure();
   exitCXXTryStmt(S);
@@ -385,12 +383,20 @@ mlir::Block *CIRGenFunction::buildLandingPad() {
   case EHScope::Catch:
   case EHScope::Cleanup:
   case EHScope::Filter:
-    llvm_unreachable("NYI");
     if (auto *lpad = innermostEHScope.getCachedLandingPad())
       return lpad;
   }
 
-  llvm_unreachable("NYI");
+  {
+    // Save the current CIR generation state.
+    mlir::OpBuilder::InsertionGuard guard(builder);
+    assert(!UnimplementedFeature::generateDebugInfo() && "NYI");
+    // FIXME(cir): handle CIR relevant landing pad bits, there's no good
+    // way to assert here right now and leaving one in break important
+    // testcases. Work to fill this in is coming soon.
+  }
+
+  return nullptr;
 }
 
 mlir::Block *CIRGenFunction::getInvokeDestImpl() {
@@ -433,7 +439,8 @@ mlir::Block *CIRGenFunction::getInvokeDestImpl() {
     LP = buildLandingPad();
   }
 
-  assert(LP);
+  // FIXME(cir): this breaks important testcases, fix is coming soon.
+  // assert(LP);
 
   // Cache the landing pad on the innermost scope.  If this is a
   // non-EH scope, cache the landing pad on the enclosing scope, too.