Do not register instrumentation callbacks if property is false.

Bug: 33645959

Test: hidl_test --gtest_filter="HidlTest.WrapTest"
Change-Id: Iebbfc67bfc6badf0f16f2378b6b58755194d60db
diff --git a/base/HidlSupport.cpp b/base/HidlSupport.cpp
index 1e383a7..3cc4b14 100644
--- a/base/HidlSupport.cpp
+++ b/base/HidlSupport.cpp
@@ -156,7 +156,9 @@
 HidlInstrumentor::HidlInstrumentor(const std::string &prefix) {
     mEnableInstrumentation = property_get_bool("hal.instrumentation.enable",
                                                false);
-    registerInstrumentationCallbacks(prefix, &mInstrumentationCallbacks);
+    if (mEnableInstrumentation) {
+        registerInstrumentationCallbacks(prefix, &mInstrumentationCallbacks);
+    }
 }
 
 HidlInstrumentor:: ~HidlInstrumentor() {}