Revert "Add --serial-dexing and --verbose-dex-stats flags to Vogar"

Revert submission 2150073-vogar-oom

Reason for revert: Causes unexpected zip corruption issues.

Change-Id: I003d1b3c3fac282b8da0d663d79f695e7efc105f
diff --git a/tools/run-libcore-tests.py b/tools/run-libcore-tests.py
index 9a38c89..de1636d 100755
--- a/tools/run-libcore-tests.py
+++ b/tools/run-libcore-tests.py
@@ -430,10 +430,6 @@
   if args.mode != "jvm":
     cmd.append("--timeout {}".format(get_timeout_secs()))
     cmd.append("--toolchain d8 --language CUR")
-    # --serial-dexing instructs Vogar to spawn at most one dexer at any given
-    # moment of time which reduces overall memory usage.
-    # See http://b/233990659.
-    cmd.append("--serial-dexing")
     if args.jit:
       cmd.append("--vm-arg -Xcompiler-option --vm-arg --compiler-filter=quicken")
     cmd.append("--vm-arg -Xusejit:{}".format(str(args.jit).lower()))