ART: Use file descriptors handed out by tombstoned for traces.

There no longer needs to be any logic in ART to generate file
names and create files. The test of file creation logic has
therefore been deleted.

Test: manual, tests in other components.
Bug: 32064548

Change-Id: I9bce6ddf3270839c40060d1287e79f9bd57d75aa
diff --git a/runtime/runtime_options.def b/runtime/runtime_options.def
index 77132a8..cfc681f 100644
--- a/runtime/runtime_options.def
+++ b/runtime/runtime_options.def
@@ -100,7 +100,7 @@
 RUNTIME_OPTIONS_KEY (Unit,                ForceNativeBridge)
 RUNTIME_OPTIONS_KEY (LogVerbosity,        Verbose)
 RUNTIME_OPTIONS_KEY (unsigned int,        LockProfThreshold)
-RUNTIME_OPTIONS_KEY (std::string,         StackTraceDir)
+RUNTIME_OPTIONS_KEY (bool,                UseTombstonedTraces, false)
 RUNTIME_OPTIONS_KEY (std::string,         StackTraceFile)
 RUNTIME_OPTIONS_KEY (Unit,                MethodTrace)
 RUNTIME_OPTIONS_KEY (std::string,         MethodTraceFile,                "/data/misc/trace/method-trace-file.bin")