Remove the hard-coded path of build_verity_metadata.py.

build_image.py used to invoke build_verity_metadata.py with a hard-coded
path of 'system/extras/verity/build_verity_metadata.py', which makes it
hard to run unittests from non-$(ANDROID_BUILD_TOP) directory.

This CL adds the dependency on the tool, so that it gets installed to
$(HOST_OUT_EXECUTABLES), then removes the hard-coded path.

Bug: 74544459
Bug: 76015688
Test: `m dist`
Test: python -m unittest test_validate_target_files
Change-Id: I0dcf4eb067a0db6f099cb589eb99a151a05c7f2b
diff --git a/tools/releasetools/build_image.py b/tools/releasetools/build_image.py
index 123ec7c..2e2e088 100755
--- a/tools/releasetools/build_image.py
+++ b/tools/releasetools/build_image.py
@@ -80,8 +80,7 @@
 
 
 def GetVerityMetadataSize(partition_size):
-  cmd = ["system/extras/verity/build_verity_metadata.py", "size",
-         str(partition_size)]
+  cmd = ["build_verity_metadata.py", "size", str(partition_size)]
   output, exit_code = RunCommand(cmd, False)
   if exit_code != 0:
     return False, 0
@@ -250,9 +249,8 @@
 def BuildVerityMetadata(image_size, verity_metadata_path, root_hash, salt,
                         block_device, signer_path, key, signer_args,
                         verity_disable):
-  cmd = ["system/extras/verity/build_verity_metadata.py", "build",
-         str(image_size), verity_metadata_path, root_hash, salt, block_device,
-         signer_path, key]
+  cmd = ["build_verity_metadata.py", "build", str(image_size),
+         verity_metadata_path, root_hash, salt, block_device, signer_path, key]
   if signer_args:
     cmd.append("--signer_args=\"%s\"" % (' '.join(signer_args),))
   if verity_disable:
diff --git a/tools/releasetools/test_validate_target_files.py b/tools/releasetools/test_validate_target_files.py
index bae648f..d62ea95 100644
--- a/tools/releasetools/test_validate_target_files.py
+++ b/tools/releasetools/test_validate_target_files.py
@@ -14,21 +14,7 @@
 # limitations under the License.
 #
 
-"""Unittests for validate_target_files.py.
-
-Note: This file calls functions in build_image.py that hard-code the path in
-relative to ANDROID_BUILD_TOP (e.g.
-system/extras/verity/build_verity_metadata.py). So the test needs to be
-triggered under ANDROID_BUILD_TOP or the top-level OTA tools directory (i.e.
-the one after unzipping otatools.zip).
-
-  (from ANDROID_BUILD_TOP)
-  $ PYTHONPATH=build/make/tools/releasetools python -m unittest \\
-      test_validate_target_files
-
-  (from OTA tools directory)
-  $ PYTHONPATH=releasetools python -m unittest test_validate_target_files
-"""
+"""Unittests for validate_target_files.py."""
 
 from __future__ import print_function