ci: Ensure only specific crates are included in Rust coverage

[kostko]

Fixes #1137

[kostko]

I've cherry-picked the "Fix linking to untrusted libraries from Intel SGX SDK" commit from #1159 as this is also required here.

[codecov]

Codecov Report

Merging #1174 into master will increase coverage by 0.06%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1174      +/-   ##
==========================================
+ Coverage   56.42%   56.49%   +0.06%     
==========================================
  Files         121      121              
  Lines        9155     9155              
==========================================
+ Hits         5166     5172       +6     
+ Misses       3460     3456       -4     
+ Partials      529      527       -2

Impacted Files	Coverage Δ
go/roothash/tests/tester.go	94.16% <0%> (+1.45%)	⬆️
go/scheduler/alg/greedy_subgraphs_scheduler.go	89.47% <0%> (+5.26%)	⬆️

---

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[codecov]

Codecov Report

Merging #1174 into master will increase coverage by 0.05%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1174      +/-   ##
==========================================
+ Coverage   56.42%   56.48%   +0.05%     
==========================================
  Files         121      121              
  Lines        9155     9155              
==========================================
+ Hits         5166     5171       +5     
+ Misses       3460     3455       -5     
  Partials      529      529

Impacted Files	Coverage Δ
go/scheduler/tests/tester.go	91.42% <0%> (-2.86%)	⬇️
go/roothash/tests/tester.go	92.7% <0%> (ø)	⬆️
go/scheduler/trivial/trivial.go	75.09% <0%> (+1.16%)	⬆️
go/scheduler/alg/greedy_subgraphs_scheduler.go	89.47% <0%> (+5.26%)	⬆️

---

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[kostko]

Actually, tarpaulin seems to be doing something strange when building/linking binaries as it seems to be unable to build *-untrusted even though normal Cargo build works.

[kostko]

It may be related to xd009642/tarpaulin#126 (which mentions -C link-dead-code) so we can just disable coverage of untrusted parts for now.