Mimic minigzip behavior and only unlink files if not using -c.

[nmoinvaz]

Issue discovered in #1185:

adam@eggsbenedict ~/scratch/zlib-ng/build7 $ ~/scratch/deflatebench/deflatebench.py 
Loaded config file '/home/adam/deflatebench.conf'.
Tool: minideflate
Activated single file mode
Level 0-9: /tmp/silesia.tar  202.1 MiB   211,957,760 B
Starting run 1 of 15
Testing level 0: cdTraceback (most recent call last):
  File "/home/adam/scratch/deflatebench/deflatebench.py", line 681, in <module>
    main()
  File "/home/adam/scratch/deflatebench/deflatebench.py", line 680, in main
    benchmain()
  File "/home/adam/scratch/deflatebench/deflatebench.py", line 565, in benchmain
    compsize,comptime,decomptime,hashfail = runtest(tempfiles,level)
  File "/home/adam/scratch/deflatebench/deflatebench.py", line 341, in runtest
    os.unlink(compfile)
FileNotFoundError: [Errno 2] No such file or directory: '/tmp/zlib-testfil.gz'

[codecov]

Codecov Report

Merging #1238 (8482235) into develop (98d4908) will decrease coverage by 0.67%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           develop    #1238      +/-   ##
===========================================
- Coverage    88.02%   87.34%   -0.68%     
===========================================
  Files          114      114              
  Lines        10192    10143      -49     
  Branches      2550     2538      -12     
===========================================
- Hits          8971     8859     -112     
+ Misses         970      962       -8     
- Partials       251      322      +71     

Flag	Coverage Δ
macos_clang	30.95% <ø> (ø)
macos_gcc	75.01% <0.00%> (-0.01%)	⬇️
ubuntu_clang	86.55% <100.00%> (-0.76%)	⬇️
ubuntu_clang_debug	86.96% <100.00%> (+0.83%)	⬆️
ubuntu_clang_inflate_allow_invalid_dist	87.11% <100.00%> (+0.08%)	⬆️
ubuntu_clang_inflate_strict	87.36% <100.00%> (+0.10%)	⬆️
ubuntu_clang_mmap	87.55% <100.00%> (+0.20%)	⬆️
ubuntu_clang_pigz	40.99% <ø> (ø)
ubuntu_clang_pigz_no_optim	41.19% <ø> (ø)
ubuntu_clang_pigz_no_threads	40.56% <ø> (ø)
ubuntu_clang_reduced_mem	87.81% <100.00%> (+0.13%)	⬆️
ubuntu_gcc	77.09% <0.00%> (+0.78%)	⬆️
ubuntu_gcc_aarch64	77.40% <0.00%> (+0.01%)	⬆️
ubuntu_gcc_aarch64_compat_no_opt	75.47% <0.00%> (-0.02%)	⬇️
ubuntu_gcc_aarch64_no_acle	76.30% <0.00%> (-0.02%)	⬇️
ubuntu_gcc_aarch64_no_neon	76.19% <0.00%> (-0.02%)	⬇️
ubuntu_gcc_armhf	77.41% <0.00%> (+0.01%)	⬆️
ubuntu_gcc_armhf_compat_no_opt	75.38% <0.00%> (-0.02%)	⬇️
ubuntu_gcc_armhf_no_acle	77.43% <0.00%> (+0.01%)	⬆️
ubuntu_gcc_armhf_no_neon	77.19% <0.00%> (+0.01%)	⬆️
ubuntu_gcc_armsf	77.28% <0.00%> (+0.01%)	⬆️
ubuntu_gcc_armsf_compat_no_opt	75.05% <0.00%> (-0.02%)	⬇️
ubuntu_gcc_benchmark	74.65% <0.00%> (-0.36%)	⬇️
ubuntu_gcc_compat_no_opt	76.61% <0.00%> (+0.01%)	⬆️
ubuntu_gcc_compat_sprefix	75.13% <0.00%> (+0.40%)	⬆️
ubuntu_gcc_m32	74.87% <0.00%> (+0.02%)	⬆️
ubuntu_gcc_mingw_i686	0.00% <0.00%> (ø)
ubuntu_gcc_mingw_x86_64	0.00% <0.00%> (ø)
ubuntu_gcc_no_avx2	76.75% <0.00%> (-0.01%)	⬇️
ubuntu_gcc_no_ctz	74.80% <0.00%> (+0.02%)	⬆️
ubuntu_gcc_no_ctzll	74.83% <0.00%> (+0.02%)	⬆️
ubuntu_gcc_no_pclmulqdq	74.74% <0.00%> (-0.01%)	⬇️
ubuntu_gcc_no_sse2	76.81% <0.00%> (+0.75%)	⬆️
ubuntu_gcc_no_sse4	76.34% <0.00%> (-0.01%)	⬇️
ubuntu_gcc_o1	76.06% <0.00%> (-0.01%)	⬇️
ubuntu_gcc_osb	∅ <ø> (∅)
ubuntu_gcc_pigz	38.89% <ø> (-0.06%)	⬇️
ubuntu_gcc_pigz_aarch64	39.34% <ø> (-0.03%)	⬇️
ubuntu_gcc_ppc	73.84% <0.00%> (+0.02%)	⬆️
ubuntu_gcc_ppc64	74.59% <0.00%> (+0.02%)	⬆️
ubuntu_gcc_ppc64le	74.57% <0.00%> (+0.02%)	⬆️
ubuntu_gcc_ppc_no_power8	74.77% <0.00%> (+0.02%)	⬆️
ubuntu_gcc_s390x	74.76% <0.00%> (+0.02%)	⬆️
ubuntu_gcc_s390x_dfltcc	72.08% <0.00%> (+0.02%)	⬆️
ubuntu_gcc_s390x_dfltcc_compat	73.68% <0.00%> (+<0.01%)	⬆️
ubuntu_gcc_s390x_no_crc32	74.52% <0.00%> (+0.02%)	⬆️
ubuntu_gcc_sparc64	74.65% <0.00%> (+0.02%)	⬆️
ubuntu_gcc_sprefix	74.92% <0.00%> (+0.39%)	⬆️
win64_gcc	?
win64_gcc_compat_no_opt	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
test/minideflate.c	58.57% <100.00%> (+0.77%)	⬆️
zutil_p.h	77.77% <0.00%> (-22.23%)	⬇️
test/fuzz/fuzzer_minigzip.c	50.38% <0.00%> (-20.32%)	⬇️
test/fuzz/fuzzer_example_dict.c	70.66% <0.00%> (-19.46%)	⬇️
test/fuzz/fuzzer_example_small.c	76.66% <0.00%> (-17.09%)	⬇️
test/fuzz/fuzzer_example_large.c	75.00% <0.00%> (-15.67%)	⬇️
test/fuzz/fuzzer_example_flush.c	79.36% <0.00%> (-13.06%)	⬇️
test/test_compare256.cc	60.00% <0.00%> (-4.00%)	⬇️
gzlib.c	70.77% <0.00%> (-0.33%)	⬇️
test/fuzz/fuzzer_compress.c	97.50% <0.00%> (-0.18%)	⬇️
... and 4 more

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