Consider binder bitness while looking for abi references.

Binder bitness does not always correlate directly with primary arch, as
assumed earlier. For example: it is possible to have devices with
primary arch 'arm' and use 64 bit binder.

Bug: 74362434

Test: utils/create_reference_dumps.py;
      m -j vndk_package for aosp_arm64_ab, aosp_arm_ab invokes
      header-abi-diff on both arm and arm64 arches.

Test: mm -j64 in system/libhwbinder on troublesome internal target.

Change-Id: Iea0a24b57cdb3033e25b6fe126c5d5d717f45b4e

android/paths.go

@@ -800,8 +800,8 @@ func PathForVndkRefAbiDump(ctx ModuleContext, version, fileName string, vndkOrNd
 	if len(arches) == 0 {
 		panic("device build with no primary arch")
 	}
-	primary_arch := arches[0].ArchType.String()
-	refDumpFileStr := "prebuilts/abi-dumps/" + vndkOrNdkDir + "/" + version + "/" + primary_arch + "/" +
+	binderBitness := ctx.DeviceConfig().BinderBitness()
+	refDumpFileStr := "prebuilts/abi-dumps/" + vndkOrNdkDir + "/" + version + "/" + binderBitness + "/" +
 		archNameAndVariant + "/" + sourceOrBinaryDir + "/" + fileName + ext
 	return ExistentPathForSource(ctx, refDumpFileStr)
 }