Unmap appcompat properties in property benchmark

Otherwise, they'll leak and cause failures

Fixes: 305838406
Test: adb shell /data/benchmarktest/bionic-benchmarks/bionic-benchmarks --benchmark_filter=BM_property
Change-Id: I2d6ed4aa30012dd7aa92eed8dc564699e6505c8f
diff --git a/benchmarks/property_benchmark.cpp b/benchmarks/property_benchmark.cpp
index ff3618e..1b4ba23 100644
--- a/benchmarks/property_benchmark.cpp
+++ b/benchmarks/property_benchmark.cpp
@@ -101,6 +101,9 @@
     }
 
     system_properties_.contexts_->FreeAndUnmap();
+    if (system_properties_.appcompat_override_contexts_) {
+      system_properties_.appcompat_override_contexts_->FreeAndUnmap();
+    }
 
     for (int i = 0; i < nprops; i++) {
       delete names[i];