remount: Merge 'remount' and 'set-verity-state'

Dedup fs_mgr_remount.cpp and set-verity-state.cpp by merging them
together and make '/system/bin/set-verity-state' a symlink to
'/system/bin/remount'.

Bug: 241688845
Test: adb-remount-test
Change-Id: I42a2344b9bdac112bf8767d428a99cb020267546
diff --git a/fs_mgr/Android.bp b/fs_mgr/Android.bp
index bebf19e..dd61272 100644
--- a/fs_mgr/Android.bp
+++ b/fs_mgr/Android.bp
@@ -251,41 +251,8 @@
     },
     symlinks: [
         "clean_scratch_files",
-    ],
-}
-
-cc_binary {
-    name: "set-verity-state",
-    srcs: ["set-verity-state.cpp"],
-    shared_libs: [
-        "libbase",
-        "libbinder",
-        "libcrypto",
-        "libcrypto_utils",
-        "libfs_mgr_binder",
-        "libutils",
-    ],
-    static_libs: [
-        "libavb_user",
-    ],
-    header_libs: [
-        "libcutils_headers",
-    ],
-
-    cflags: ["-Werror"],
-    cppflags: [
-        "-DALLOW_DISABLE_VERITY=0",
-    ],
-    product_variables: {
-        debuggable: {
-            cppflags: [
-                "-UALLOW_DISABLE_VERITY",
-                "-DALLOW_DISABLE_VERITY=1",
-            ],
-        },
-    },
-    symlinks: [
-        "enable-verity",
         "disable-verity",
+        "enable-verity",
+        "set-verity-state",
     ],
 }