adding /out/soong_injection/metrics/converted_modules_path_map.json

This file can be used by atest/scripts/tools to determine which modules
have been converted and what their bazel build path is.

Test: b build //packages/modules/adb/...
will generate the file at /out/soong_injection/metrics/converted_modules_path_map.json
Also added a unit test to check that the file is created.

{
  "adbd": "//packages/modules/adb",
  "adbd_test": "//packages/modules/adb",
  "add_ext4_encrypt": "//external/e2fsprogs/contrib",
  ....
}

Change-Id: Ibd424c487840d84c8a4fb635828a73541220b36b
diff --git a/bp2build/conversion.go b/bp2build/conversion.go
index b6190c6..522c10e 100644
--- a/bp2build/conversion.go
+++ b/bp2build/conversion.go
@@ -34,6 +34,12 @@
 
 	files = append(files, newFile("metrics", "converted_modules.txt", strings.Join(metrics.convertedModules, "\n")))
 
+	convertedModulePathMap, err := json.MarshalIndent(metrics.convertedModulePathMap, "", "\t")
+	if err != nil {
+		panic(err)
+	}
+	files = append(files, newFile("metrics", "converted_modules_path_map.json", string(convertedModulePathMap)))
+
 	files = append(files, newFile("product_config", "soong_config_variables.bzl", cfg.Bp2buildSoongConfigDefinitions.String()))
 
 	files = append(files, newFile("product_config", "arch_configuration.bzl", android.StarlarkArchConfigurations()))