RFR (M): Make TSAN a build-time JVM feature

[Man Cao]

Hi,

Could I get review for this:
http://cr.openjdk.java.net/~manc/tsan/20190329/webrev.00/

It makes it possible to disable TSAN at build time, using
"--with-jvm-features=-tsan". My initial purpose was to add a "#ifdef" macro
for TSAN, but it seems making TSAN a JVM feature is the right way to go for
the long term.

Tested by building with and without TSAN, and running LD_PRELOAD.

-Man