Improve bazel action status mnemonics

Example output line:

```
CppCompile: [bazel-out/android_arm-fastbuild-ST-dd3fdd7bf572/bin/bionic/libc/_objs/libc_bionic_asm/
0/strcpy.o]
```

Instead of just `CppCompile`.

Fixes: 220234318
Test: `m libc` in mixed builds
Change-Id: I3e079006b1f1bb9e8db5b4f022ea993d7693aeb5
diff --git a/android/bazel_handler.go b/android/bazel_handler.go
index 0052551..cb45f2a 100644
--- a/android/bazel_handler.go
+++ b/android/bazel_handler.go
@@ -848,7 +848,8 @@
 		// build statement have later timestamps than the outputs.
 		rule.Restat()
 
-		rule.Build(fmt.Sprintf("bazel %d", index), buildStatement.Mnemonic)
+		desc := fmt.Sprintf("%s: %s", buildStatement.Mnemonic, buildStatement.OutputPaths)
+		rule.Build(fmt.Sprintf("bazel %d", index), desc)
 	}
 }