Add AddressSanitizer and LeakSanitizer to ci/local dev

[fcostaoliveira]

This PR adds memory leak detection to the CI pipeline using AddressSanitizer (ASAN) and LeakSanitizer (LSAN). It also include local dev how-to placed inside the Readme.

Furthermore, just by running it we've caught a leak (very small one of 10B) in uri usage.

 	debug:	==7533==ERROR: LeakSanitizer: detected memory leaks
	debug:	
	debug:	Direct leak of 10 byte(s) in 1 object(s) allocated from:
	debug:	    #0 0x7f9d31af74e8 in strdup ../../../../src/libsanitizer/asan/asan_interceptors.cpp:578
	debug:	    #1 0x55a8f5521454 in parse_uri /home/runner/work/memtier_benchmark/memtier_benchmark/memtier_benchmark.cpp:391
	debug:	    #2 0x55a8f5521454 in main /home/runner/work/memtier_benchmark/memtier_benchmark/memtier_benchmark.cpp:1523
	debug:	    #3 0x7f9d30c2a1c9  (/lib/x86_64-linux-gnu/libc.so.6+0x2a1c9) (BuildId: 274eec488d230825a136fa9c4d85370fed7a0a5e)
	debug:	    #4 0x7f9d30c2a28a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2a28a) (BuildId: 274eec488d230825a136fa9c4d85370fed7a0a5e)
	debug:	    #5 0x55a8f55188e4 in _start (/home/runner/work/memtier_benchmark/memtier_benchmark/memtier_benchmark+0x148e4) (BuildId: 68811aba3179c25bdd8473c5efd53cf1ae64f831)
	debug:	
	debug:	SUMMARY: AddressSanitizer: 10 byte(s) leaked in 1 allocation(s).

This confirms the automation is working and usefull.

Changes

Build System

• Added --enable-sanitizers configure option to enable ASAN/LSAN
• When enabled, automatically adds appropriate compiler and linker flags
• Default build behavior unchanged (sanitizers are opt-in)

CI Pipeline

• Added new workflow .github/workflows/asan.yml
• Runs on ubuntu-latest for all pushes and pull requests
• Builds memtier_benchmark with sanitizers enabled
• Executes full test suite with leak detection:
  • OSS TCP and TLS (v1.2, v1.3)
  • OSS-CLUSTER TCP and TLS
• Build fails if any memory leaks or errors are detected

Test Dependencies

• Removed external mbdirector dependency given it conflicted with rltest versioning
• Replaced with local implementation in tests/mb.py
• Upgraded rltest from 0.6.0 to >=0.7.17

Testing

All tests pass cleanly with ASAN/LSAN enabled, confirming no memory leaks in the current codebase.

Local verification:

./configure --enable-sanitizers
make -j
ASAN_OPTIONS=detect_leaks=1 ./tests/run_tests.sh

[paulorsousa]

🚀 👏