Fix ELF core register sections and PE64 creation ##bin

[trufae]

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Fix the two expected failures encountered while validating the OSS Scanner enrollment: ELF: core sections with reg name and create pe x86-64.

Two commits:

• Expose ELF core .reg, .reg2, and .reg-xstate sections, with thread IDs and aliases for the first thread. Share bounded note parsing with register-state extraction, check note owners and descriptor lengths, and correct the i386 register-set size.
• Add the PE64 creation callback and share the writer with PE32. Honor the requested bitness, emit complete aligned headers and sections, and map optional data into a writable data section. Previously, pe64 could not create a file and pe -b 64 silently emitted PE32.

Remove both BROKEN markers. Check actual register-section names, offsets and sizes, and generated PE architecture, header magic, entry-point bytes and data mapping. Add malformed-note and multiple-thread coverage. PE output now uses standard file/section alignment rather than the former overlapping 125-byte layout.

The existing core disassembly expectation loses segment metadata comments because radare2 suppresses them when sections are present; register values and instructions are unchanged.

Validation:

• Root make -j4 and installation succeeded.
• r2r -u -L -C test db/formats/elf db/formats/pe: 771 passed, 0 failed, 0 broken, 2 skipped.
• All 14 focused core-note and PE-creation tests pass.
• Independently checked ELF register-section offsets and generated PE64 headers with objdump.
• git diff --check passes.

Validation ran on Linux; generated PE files were parsed, not executed on Windows.