Test --x86-asm-syntax=intel only on amd64

[kalyanac]

Some llvm-objdump installations may not include all backends and will cause failures.

[kalyanac]

Sorry about the multiple commits. I tried to create the commit directly from Github's editor and that did not go well.

[kalyanac]

Test failures are benign and unrelated.

[codecov-commenter]

Codecov Report

Merging #561 into master will decrease coverage by 1.33%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #561      +/-   ##
==========================================
- Coverage   68.46%   67.12%   -1.34%     
==========================================
  Files          78       78              
  Lines       16108    14062    -2046     
==========================================
- Hits        11028     9439    -1589     
+ Misses       4225     3790     -435     
+ Partials      855      833      -22     

Impacted Files	Coverage Δ
internal/driver/settings.go	67.21% <0.00%> (-5.01%)	⬇️
...ithub.com/google/pprof/internal/driver/settings.go	67.21% <0.00%> (-5.01%)	⬇️
internal/binutils/addr2liner_llvm.go	64.51% <0.00%> (-4.06%)	⬇️
profile/proto.go	79.53% <0.00%> (-3.73%)	⬇️
src/github.com/google/pprof/profile/proto.go	79.53% <0.00%> (-3.73%)	⬇️
internal/driver/flags.go	15.38% <0.00%> (-3.67%)	⬇️
...c/github.com/google/pprof/internal/driver/flags.go	15.38% <0.00%> (-3.67%)	⬇️
...b.com/google/pprof/internal/binutils/addr2liner.go	65.43% <0.00%> (-3.46%)	⬇️
.../google/pprof/internal/binutils/addr2liner_llvm.go	70.96% <0.00%> (-3.32%)	⬇️
internal/driver/fetch.go	62.88% <0.00%> (-3.17%)	⬇️
... and 68 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update acf8798...814099a. Read the comment docs.

[kalyanac]

Failure is unrelated.

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@29d1258). Click here to learn what that means.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #561   +/-   ##
=========================================
  Coverage          ?   67.14%           
=========================================
  Files             ?       78           
  Lines             ?    14072           
  Branches          ?        0           
=========================================
  Hits              ?     9449           
  Misses            ?     3788           
  Partials          ?      835           

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 29d1258...e2b2322. Read the comment docs.