Remove extra go.mod files

Only the top level build/soong/go.mod file should exist, any extras
breaks `go test ./...` in build/soong, and also breaks the kythe build
that produces xrefs for code search.

Bug: 315537199
Test: go test ./...
Change-Id: Id5262550654ff1559cfb3fa1ecdae95c126109df
diff --git a/testing/code_metadata_internal_proto/go.mod b/testing/code_metadata_internal_proto/go.mod
deleted file mode 100644
index 7e9129d..0000000
--- a/testing/code_metadata_internal_proto/go.mod
+++ /dev/null
@@ -1,3 +0,0 @@
-module android/soong/testing/code_metadata_internal_proto
-
-go 1.18
diff --git a/testing/code_metadata_proto/go.mod b/testing/code_metadata_proto/go.mod
deleted file mode 100644
index ada2411..0000000
--- a/testing/code_metadata_proto/go.mod
+++ /dev/null
@@ -1,3 +0,0 @@
-module android/soong/testing/code_metadata_proto
-
-go 1.18
diff --git a/testing/test_spec_proto/go.mod b/testing/test_spec_proto/go.mod
deleted file mode 100644
index b581aac..0000000
--- a/testing/test_spec_proto/go.mod
+++ /dev/null
@@ -1,3 +0,0 @@
-module android/soong/testing/test_spec_proto
-
-go 1.18