RFR: 8313435: Clean up unused default methods code [v5]

[David Holmes]

On Thu, 3 Aug 2023 12:25:50 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> Default methods processing code has unused code (that gets -Wconversion warnings) from when it was used to create bridge (called overpass) method for an early implementation of generic reification in Hotspot.
>> 
>> This change removes unused bytecodeAssembler code and adds a check for methods and constant pool overflow.
>> Tested with tier1 and runtime/lambda-features tests.
>
> Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Make assert an exception.

I'm not at all sure that `BytecodeConstantPool::find_or_add` needs to throw, especially given that requires polluting so much code with TRAPS and CHECK - it looks really awful to see things like:

assem._new(errorName, CHECK_0));

Maybe we should be checking for sufficient space at a higher-level somewhere? I'm not familiar with how this code is actually used.

This seems to have strayed somewhat from the primary cleanup of unused code.

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Changes requested by dholmes (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/15095#pullrequestreview-1562016358