RFR: 8261125: Move VM_Operation to vmOperation.hpp [v2]

[Ioi Lam]

> vmOperations.hpp declares the VM_Operation class, as well as a hodge podge of subclasses such as VM_ForceSafepoint, VM_DeoptimizeFrame.
> 
> Out of the 1000 hotspot .o files, about 680 include vmOperations.hpp (mostly transitively). In most cases, they just need to use the VM_Operation class.
> 
> So we should move VM_Operation to its own header: vmOperation.hpp (no "s").
> 
> After the refactoring, vmOperations.hpp is included only 64 times. The inclusion count of threadSMR.hpp is also reduced from 687 to 99. HotSpot build time is improved by about 0.4%.
> 
> Tested with mach5: tier1, builds-tier2, builds-tier3, builds-tier4 and builds-tier5. Also locally: aarch64, arm, ppc64, s390, x86, and zero.

Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:

  interfaceSupport.inline.hpp needs VM_Exit from vmOperations.hpp for JVM_LEAF macro

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2398/files
  - new: https://git.openjdk.java.net/jdk/pull/2398/files/f4637f70..01633cda

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2398&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2398&range=00-01

  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2398.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2398/head:pull/2398

PR: https://git.openjdk.java.net/jdk/pull/2398