Add clone arguments to callback hooks

[vancemiller]

Forwards all arguments from clone to the parent and child hook functions. Additionally, allows the parent hook to set the returned PID if desired. Updates the clone test case to verify arguments are correctly forwarded.

Very similar to PR #102 but also updates the test case.

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This change is 

[codecov-commenter]

Codecov Report

Merging #111 (58e3205) into master (2c8765f) will increase coverage by 0.31%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #111      +/-   ##
==========================================
+ Coverage   91.98%   92.29%   +0.31%     
==========================================
  Files          12       12              
  Lines         973      974       +1     
==========================================
+ Hits          895      899       +4     
+ Misses         78       75       -3     

Flag	Coverage Δ
pmemfile_tests	86.28% <33.33%> (+0.04%)	⬆️
regular_tests	91.17% <100.00%> (+0.11%)	⬆️

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Impacted Files	Coverage Δ
include/libsyscall_intercept_hook_point.h	50.00% <ø> (ø)
src/intercept.c	81.59% <100.00%> (+0.73%)	⬆️
src/intercept_log.c	95.60% <0.00%> (+0.73%)	⬆️

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