test: expand MIB.Compiler tests (46.15%)
Added 34 comprehensive tests covering:
- compile_string/2 - String compilation (7 tests)
- compile/2 - File compilation (2 tests)
- Integration with Parser (1 test)
- compile_all/2 - Batch compilation (4 tests)
- load_compiled/1 - Load compiled MIBs (3 tests)
- Compile options (validate, format, output_dir, optimize, etc.) (8 tests)
- Error handling (syntax errors, missing files, parse errors) (3 tests)
- Symbol table construction (2 tests)
- Dependency extraction (deduplication, single/multiple) (4 tests)
- Compiled MIB structure validation (2 tests)
All tests tagged @moduletag :yecc_required (excluded by default).
Tests use temporary directories for file I/O.Coverage: 46.15% (unchanged - tests excluded)
Total tests: 1,514 (all passing, 72 excluded)