Add proto for Test ownership metadata.

This Cl adds a new rule to Soong to generate test spec metadata. Also, this CL adds a provider in various test module to provide test spec related data to the Soong rule.
Will add providers and test code to other Module in the future changes.
Provider added for the following test modules in this change: android_robolectric_test, android_test, bootclasspath_fragment_test, java_test, java_test_host, python_test, python_test_host, sh_test,and sh_test_host.

Bug: 296873595

Change-Id: I5f89f72d5874bb7838ae357efdb8c6ca208e18a7
diff --git a/testing/Android.bp b/testing/Android.bp
new file mode 100644
index 0000000..26a7d93
--- /dev/null
+++ b/testing/Android.bp
@@ -0,0 +1,19 @@
+package {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+bootstrap_go_package {
+    name: "soong-testing",
+    pkgPath: "android/soong/testing",
+    deps: [
+        "blueprint",
+        "soong-android",
+        "soong-testing-test_spec_proto",
+
+    ],
+    srcs: [
+        "test_spec.go",
+        "init.go",
+    ],
+    pluginFor: ["soong_build"],
+}