[MLIR][LLVM] Fix import split marker in alias test (#127540)

Author: xlauko

mlir/test/Target/LLVMIR/Import/alias.ll

@@ -12,7 +12,7 @@ entry:
   ret ptr null
 }
 
-; -----
+; // -----
 
 @zed = global i32 42
 @foo = alias i32, ptr @zed
@@ -27,7 +27,7 @@ entry:
 ; CHECK:   llvm.return %[[ADDR]] : !llvm.ptr
 ; CHECK: }
 
-; -----
+; // -----
 
 @v1 = global i32 0
 @a3 = alias i32, addrspacecast (ptr @v1 to ptr addrspace(2))
@@ -37,7 +37,7 @@ entry:
 ; CHECK:   llvm.return %[[CASTED_ADDR]] : !llvm.ptr<2>
 ; CHECK: }
 
-; -----
+; // -----
 
 @some_name = constant { [3 x ptr] } { [3 x ptr] [ptr null, ptr null, ptr null] }
 @vtable = alias { [3 x ptr] }, ptr @some_name
@@ -47,7 +47,7 @@ entry:
 ; CHECK:   llvm.return %[[ADDR]] : !llvm.ptr
 ; CHECK: }
 
-; -----
+; // -----
 
 @glob.private = private constant [32 x i32] zeroinitializer
 @glob = linkonce_odr hidden alias [32 x i32], inttoptr (i64 add (i64 ptrtoint (ptr @glob.private to i64), i64 1234) to ptr)
@@ -60,7 +60,7 @@ entry:
 ; CHECK: %[[RET:.*]] = llvm.inttoptr %[[INTTOPTR]] : i64 to !llvm.ptr
 ; CHECK: llvm.return %[[RET]] : !llvm.ptr
 
-; -----
+; // -----
 
 @g1 = private global i32 0
 @g2 = internal constant ptr @a1