Don't _PyObject_GC_TRACK(frame) before using it.
After evaluation is finished, do tracking only if refcnt is not one.

result without --enable-optimization:
$ ~/local/cpython/bin/pyperf compare_to default.json.gz patched.json.gz -G
Slower (15):
- scimark_sparse_mat_mult: 5.83 ms +- 0.03 ms -> 6.12 ms +- 0.35 ms: 1.05x slower (+5%)
- sympy_expand: 734 ms +- 21 ms -> 765 ms +- 40 ms: 1.04x slower (+4%)
- sympy_str: 327 ms +- 10 ms -> 339 ms +- 13 ms: 1.04x slower (+4%)
- scimark_fft: 498 ms +- 2 ms -> 512 ms +- 2 ms: 1.03x slower (+3%)
- scimark_monte_carlo: 172 ms +- 3 ms -> 175 ms +- 4 ms: 1.02x slower (+2%)
- chameleon: 17.6 ms +- 0.3 ms -> 17.9 ms +- 0.2 ms: 1.02x slower (+2%)
- telco: 11.3 ms +- 0.4 ms -> 11.5 ms +- 0.6 ms: 1.02x slower (+2%)
- logging_simple: 19.0 us +- 0.3 us -> 19.2 us +- 0.3 us: 1.01x slower (+1%)
- pickle_dict: 52.2 us +- 0.3 us -> 52.9 us +- 0.2 us: 1.01x slower (+1%)
- pickle_list: 6.86 us +- 0.04 us -> 6.94 us +- 0.05 us: 1.01x slower (+1%)
- pickle: 17.4 us +- 0.2 us -> 17.6 us +- 0.2 us: 1.01x slower (+1%)
- logging_silent: 556 ns +- 13 ns -> 561 ns +- 11 ns: 1.01x slower (+1%)
- sqlite_synth: 5.25 us +- 0.44 us -> 5.28 us +- 0.15 us: 1.01x slower (+1%)
- pidigits: 248 ms +- 2 ms -> 249 ms +- 2 ms: 1.00x slower (+0%)
- unpack_sequence: 73.5 ns +- 0.6 ns -> 73.8 ns +- 2.4 ns: 1.00x slower (+0%)

Faster (27):
- call_method_slots: 11.4 ms +- 0.1 ms -> 10.7 ms +- 0.1 ms: 1.07x faster (-6%)
- call_method: 11.5 ms +- 0.1 ms -> 10.8 ms +- 0.2 ms: 1.06x faster (-6%)
- call_simple: 10.7 ms +- 0.3 ms -> 10.1 ms +- 0.3 ms: 1.06x faster (-5%)
- regex_effbot: 4.08 ms +- 0.05 ms -> 3.97 ms +- 0.04 ms: 1.03x faster (-3%)
- regex_compile: 318 ms +- 11 ms -> 310 ms +- 10 ms: 1.03x faster (-3%)
- html5lib: 154 ms +- 4 ms -> 150 ms +- 4 ms: 1.03x faster (-3%)
- deltablue: 13.5 ms +- 0.5 ms -> 13.1 ms +- 0.4 ms: 1.03x faster (-3%)
- call_method_unknown: 13.1 ms +- 0.1 ms -> 12.8 ms +- 0.1 ms: 1.02x faster (-2%)
- richards: 131 ms +- 2 ms -> 128 ms +- 2 ms: 1.02x faster (-2%)
- meteor_contest: 170 ms +- 3 ms -> 167 ms +- 4 ms: 1.02x faster (-2%)
- sympy_integrate: 34.7 ms +- 0.7 ms -> 34.0 ms +- 0.2 ms: 1.02x faster (-2%)
- spectral_norm: 210 ms +- 2 ms -> 206 ms +- 2 ms: 1.02x faster (-2%)
- dulwich_log: 115 ms +- 1 ms -> 113 ms +- 2 ms: 1.01x faster (-1%)
- genshi_text: 54.1 ms +- 0.8 ms -> 53.4 ms +- 0.5 ms: 1.01x faster (-1%)
- 2to3: 511 ms +- 3 ms -> 505 ms +- 2 ms: 1.01x faster (-1%)
- pathlib: 28.8 ms +- 0.6 ms -> 28.5 ms +- 0.8 ms: 1.01x faster (-1%)
- xml_etree_parse: 199 ms +- 3 ms -> 198 ms +- 2 ms: 1.01x faster (-1%)
- hexiom: 17.9 ms +- 0.1 ms -> 17.7 ms +- 0.1 ms: 1.01x faster (-1%)
- mako: 35.1 ms +- 1.0 ms -> 34.9 ms +- 0.3 ms: 1.01x faster (-1%)
- nbody: 194 ms +- 1 ms -> 193 ms +- 1 ms: 1.01x faster (-1%)
- unpickle_pure_python: 634 us +- 15 us -> 630 us +- 10 us: 1.01x faster (-1%)
- unpickle_list: 6.16 us +- 0.06 us -> 6.13 us +- 0.05 us: 1.01x faster (-1%)
- genshi_xml: 113 ms +- 3 ms -> 112 ms +- 1 ms: 1.01x faster (-1%)
- json_dumps: 19.1 ms +- 0.3 ms -> 19.1 ms +- 0.2 ms: 1.00x faster (-0%)
- python_startup: 13.3 ms +- 0.1 ms -> 13.3 ms +- 0.1 ms: 1.00x faster (-0%)
- python_startup_no_site: 8.24 ms +- 0.06 ms -> 8.22 ms +- 0.04 ms: 1.00x faster (-0%)
- go: 421 ms +- 3 ms -> 421 ms +- 3 ms: 1.00x faster (-0%)

Benchmark hidden because not significant (22): chaos, crypto_pyaes, django_template, fannkuch, float, json_loads, logging_format, nqueens, pickle_pure_python, raytrace, regex_dna, regex_v8, scimark_lu, scimark_sor, sqlalchemy_declarative, sqlalchemy_imperative, sympy_sum, tornado_http, unpickle, xml_etree_generate, xml_etree_iterparse, xml_etree_process