refactor parts of jvm.h into jvm_io.h and jvm_constants.h

jvm.h is over 1000 lines long. It is included by 940 out of 1000 HotSpot .o files. However, most of the HotSpot source files just use a small fraction of jvm.h:

- the jio_xxxprintf() functions
- the JVM_RECOGNIZED_XXX_MODIFIERS defines

We should move these two parts into jvm_io.h and jvm_constants.h. This reduces the files that include jvm.h to about 82 files. Build time of HotSpot is reduced by about 0.4%.