liblp: test: fix liblp.UpdateAnyMetadataSlot

Move test to verify we can't read unwritten metadata from
liblp.UpdateAnyMetadataSlot to liblp.CreateFakeDisk.

Test: gTest liblpg_test
Bug: 109821005
Change-Id: I4714c949e2b2d9de6444996a2af2992a821c4a85
diff --git a/fs_mgr/liblp/io_test.cpp b/fs_mgr/liblp/io_test.cpp
index 329a901..eda68fd 100644
--- a/fs_mgr/liblp/io_test.cpp
+++ b/fs_mgr/liblp/io_test.cpp
@@ -117,6 +117,9 @@
     uint64_t size;
     ASSERT_TRUE(GetDescriptorSize(fd, &size));
     ASSERT_EQ(size, kDiskSize);
+
+    // Verify that we can't read unwritten metadata.
+    ASSERT_EQ(ReadMetadata(fd, 1), nullptr);
 }
 
 // Flashing metadata should not work if the metadata was created for a larger
@@ -191,9 +194,6 @@
     ASSERT_EQ(imported->partitions.size(), 1);
     EXPECT_EQ(GetPartitionName(imported->partitions[0]), "system");
 
-    // Verify that we can't read unwritten metadata.
-    ASSERT_EQ(ReadMetadata(fd, 1), nullptr);
-
     // Change the name before writing to the next slot.
     strncpy(imported->partitions[0].name, "vendor", sizeof(imported->partitions[0].name));
     ASSERT_TRUE(UpdatePartitionTable(fd, *imported.get(), 1));