RFR: Small fixes - shipment one

[Robbin Ehn]

Reducing the number of variables, the number of assignment to each variable, white-spaces, renamed some variables, removed unnecessary template, etc...
Except the removal of template 'bottom', the code is the same. (assert is moved up one level)

Passes 1-3 (no new failures)
It seem to be slightly faster than before, but at least on par.

This is not complete at all, but to avoid merge conflict I want to ship, and also make someone happy about removing a template.

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Commit messages:
 - Reverted wrong accidential change
 - Fixed assert on uninit var
 - Removed unused template
 - Rename, whitespace, brackets, assignment
 - Removed unused variable
 - Use chunk sp directly in if statement
 - Renamed some variables
 - Don't cache _cont.argsize()
 - Fixed init_chunk
 - Single if bail-out fast path failure
 - ... and 6 more: https://git.openjdk.java.net/loom/compare/16e4713c...475d195a

Changes: https://git.openjdk.java.net/loom/pull/114/files
 Webrev: https://webrevs.openjdk.java.net/?repo=loom&pr=114&range=00
  Stats: 134 lines in 7 files changed: 19 ins; 27 del; 88 mod
  Patch: https://git.openjdk.java.net/loom/pull/114.diff
  Fetch: git fetch https://git.openjdk.java.net/loom pull/114/head:pull/114

PR: https://git.openjdk.java.net/loom/pull/114