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_test.go b/bp2build/conversion_test.go
index 0cb711c..b696a98 100644
--- a/bp2build/conversion_test.go
+++ b/bp2build/conversion_test.go
@@ -116,6 +116,10 @@
 			basename: "converted_modules.txt",
 		},
 		{
+			dir:      "metrics",
+			basename: "converted_modules_path_map.json",
+		},
+		{
 			dir:      "product_config",
 			basename: "soong_config_variables.bzl",
 		},