8266018: Shenandoah: fix an incorrect assert

Reviewed-by: rkennke
Backport-of: 2dd56676fb564072f73f5fd9e591bda7922523ac
diff --git a/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp b/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp
index a3263da..d07fc1a 100644
--- a/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp
+++ b/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp
@@ -690,7 +690,7 @@
   } else if (mem->is_MergeMem()) {
     res = mem->as_MergeMem()->memory_at(alias);
   } else if (mem->is_Store() || mem->is_LoadStore() || mem->is_ClearArray()) {
-    assert(alias = Compile::AliasIdxRaw, "following raw memory can't lead to a barrier");
+    assert(alias == Compile::AliasIdxRaw, "following raw memory can't lead to a barrier");
     res = mem->in(MemNode::Memory);
   } else {
 #ifdef ASSERT