gsi_util: try to use executable in local bin/ folder

cmd_utils.run_command() will try to find the executable file
in the local bin/ folder firstly.

The patch also add some missing dependency files and make sure
gsi_util could run alone.

Bug: 75992357
Test: ./run_test.py
Test: './build.py setup_env',
  then './gsi_util.bin check_compat --system adb --vendor adb' in
  another terminal without lunch

Change-Id: I923eb68b4a6829c8ed5e5d8278e97fd4f5860efc

gsi/gsi_util/build.py

@@ -37,6 +37,8 @@ REQUIRED_ITEMS = [
     RequiredItem('bin/checkvintf', 'bin/checkvintf'),
     RequiredItem('lib64/libbase.so', 'lib64/libbase.so'),
     RequiredItem('lib64/liblog.so', 'lib64/liblog.so'),
+    RequiredItem('bin/secilc', 'bin/secilc'),
+    RequiredItem('lib64/libsepol.so', 'lib64/libsepol.so'),
     RequiredItem('bin/simg2img', 'bin/simg2img'),
     RequiredItem('lib64/libc++.so', 'lib64/libc++.so'),
 ]  # pyformat: disable