RFR: 8225779: Remove unused CollectedHeap::cell_header_size()

[Aleksey Shipilev]

On 6/14/19 8:29 AM, Per Liden wrote:
> CollectedHeap::cell_header_size() is no longer used and can be removed. This patch is a hg backout
> of [1] where it was introduced, plus the two followup bug fixes [2] & [3].
> 
> This is a clean backout, with the exception of light editing needed in two places, because:
> 
> 1) The function Universe::narrow_oop_base() has since been renamed to CompressedOops::base().
> 2) The include guard CPU_ARM_VM_MACROASSEMBLER_ARM_HPP has since been renamed to
> CPU_ARM_MACROASSEMBLER_ARM_HPP.
> 
> Testing: Tier1-3 on all Oracle platforms
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8225779
> Webrev: http://cr.openjdk.java.net/~pliden/8225779/webrev.0

Looks fine. Shenandoah does not need it anymore, because there are no accesses beyond the "regular"
objects anymore -- this is why it is not actually used. The patch passes hotspot_gc_shenandoah anyway.

-- 
Thanks,
-Aleksey