idmap2: fix clang-tidy warnings [modernize-*]

Bug: 120024673
Test: mmm frameworks/base/cmds/idmap2; check output
Change-Id: I8768169fb7b541eb6b1aa3311c46a710eb71aac9
diff --git a/cmds/idmap2/tests/Idmap2BinaryTests.cpp b/cmds/idmap2/tests/Idmap2BinaryTests.cpp
index 255f3c1..22f48e9 100644
--- a/cmds/idmap2/tests/Idmap2BinaryTests.cpp
+++ b/cmds/idmap2/tests/Idmap2BinaryTests.cpp
@@ -46,8 +46,7 @@
 using ::android::util::ExecuteBinary;
 using ::testing::NotNull;
 
-namespace android {
-namespace idmap2 {
+namespace android::idmap2 {
 
 class Idmap2BinaryTests : public Idmap2Tests {};
 
@@ -313,5 +312,4 @@
   ASSERT_NE(result->status, EXIT_SUCCESS);
 }
 
-}  // namespace idmap2
-}  // namespace android
+}  // namespace android::idmap2