RFR (S) 8211926: Catastrophic size_t underflow in BitMap::*_large methods

[Aleksey Shipilev]

Bug:
  https://bugs.openjdk.java.net/browse/JDK-8211926

Fix:
  http://cr.openjdk.java.net/~shade/8211926/webrev.01/

Found this while porting some Shenandoah addons to jdk/jdk.

I took the liberty of homogenizing the internals of those methods to always call "small" path when
range does not allow us to enter the "large" path. This protects us from accidentally breaking VM
when asserts are disabled, and makes "large" methods usable as drop-ins for "small" ones.

Testing: hotspot-tier1, new gtest, jdk-submit (running)

Thanks,
-Aleksey