gh-87092: reduce redundancy and repetition in compiler's optimization stage

[iritkatriel]

• replace calls to eliminate_empty_basic_blocks by an assertion that there are no empty blocks
• same for a couple of inlined copies of the eliminate_empty_basic_blocks logic
• rename clean_basic_block --> remove_redundant_nops for clarity
• rename normalize_basic_block --> check_cfg and reduce it to only check (not remove empty blocks).
• rename extend_block --> inline_small_exit_blocks. Make it inline blocks with linenos too (as it used to until bde06e1).
• use the IS_UNCONDITIONAL_JUMP_OPCODE macro in a couple of places instead of checking precise opcodes

• Issue: Split compiler into code-gen, optimizer and assembler. #87092

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @iritkatriel for commit 42a7525 🤖

If you want to schedule another build, you need to add the ":hammer: test-with-buildbots" label again.

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @iritkatriel for commit d06fd46 🤖

If you want to schedule another build, you need to add the ":hammer: test-with-buildbots" label again.

[iritkatriel]

@markshannon buildbots all pass with this. Any further comments?

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @iritkatriel for commit cf6d362 🤖

If you want to schedule another build, you need to add the ":hammer: test-with-buildbots" label again.

[markshannon]

A couple of questions