RFR: 8256205: Simplify compiler calling convention handling

[Vladimir Kozlov]

On Wed, 11 Nov 2020 15:35:16 GMT, Claes Redestad <redestad at openjdk.org> wrote:

> Clean up and simplify some of the calling convention handling:
> 
> - Remove Matcher::calling_convention/c_calling_convention and replace select few call sites with direct calls to SharedRuntime
> - Remove unused is_outgoing args. Since the SPARC removal the is_outgoing has no effect on the calling_convention or return_value methods.
> - Move in_preserved_stack_slots to SharedRuntime to match out_preserved_stack_slots. 
> 
> This has a tiny positive impact by reducing calls and improving inlining (at least gcc has a hard time inlining anything that goes in the .ad files, even when it's defined to the same class), but is mainly a cleanup effort.
> 
> Testing: Oracle tier1-2 testing; S390, PPC and ARM32 builds

Nice clean up.

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Marked as reviewed by kvn (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/1168