Drop libfmt dependency

Bug: 302718225
Test: mma
Change-Id: Ie5cc88c1ef42fc311769589b2c10c41d4e6abc98
diff --git a/libs/binder/tests/binderRpcTest.cpp b/libs/binder/tests/binderRpcTest.cpp
index f0400d3..c044d39 100644
--- a/libs/binder/tests/binderRpcTest.cpp
+++ b/libs/binder/tests/binderRpcTest.cpp
@@ -64,12 +64,12 @@
 
 static std::string WaitStatusToString(int wstatus) {
     if (WIFEXITED(wstatus)) {
-        return std::format("exit status {}", WEXITSTATUS(wstatus));
+        return "exit status " + std::to_string(WEXITSTATUS(wstatus));
     }
     if (WIFSIGNALED(wstatus)) {
-        return std::format("term signal {}", WTERMSIG(wstatus));
+        return "term signal " + std::to_string(WTERMSIG(wstatus));
     }
-    return std::format("unexpected state {}", wstatus);
+    return "unexpected state " + std::to_string(wstatus);
 }
 
 static void debugBacktrace(pid_t pid) {
@@ -263,9 +263,8 @@
     bool noKernel = GetParam().noKernel;
 
     std::string path = GetExecutableDirectory();
-    auto servicePath =
-            std::format("{}/binder_rpc_test_service{}{}", path,
-                        singleThreaded ? "_single_threaded" : "", noKernel ? "_no_kernel" : "");
+    auto servicePath = path + "/binder_rpc_test_service" +
+            (singleThreaded ? "_single_threaded" : "") + (noKernel ? "_no_kernel" : "");
 
     unique_fd bootstrapClientFd, socketFd;