Add rust_benchmark module to soong.

This commit adds rust_benchmark and rust_benchmark_host commands to
soong. Respectively running rust benchmarks on device and host. Currently
only criterion based benchmarks are supported and criterion library is
automatically linked.

Test: atest <module with rust_benchmark defined>
Bug: 155309706
Change-Id: I6edfc2b4bf30b1163fe59b8c2ecdcd4e7125e7b9
diff --git a/rust/Android.bp b/rust/Android.bp
index a29c474..a6c4e07 100644
--- a/rust/Android.bp
+++ b/rust/Android.bp
@@ -14,6 +14,7 @@
     ],
     srcs: [
         "androidmk.go",
+        "benchmark.go",
         "binary.go",
         "bindgen.go",
         "builder.go",
@@ -35,6 +36,7 @@
         "testing.go",
     ],
     testSrcs: [
+        "benchmark_test.go",
         "binary_test.go",
         "bindgen_test.go",
         "builder_test.go",