e2e-tests: Make symbol bar tests for Go more stable

Created by: mrnugget

After multiple flaky e2e failures on master, this does for the Go symbol bar tests what #5474 did for the Java symbol bar tests.

It changes the test "fixtures" to use directories/files with less symbols so that the content of the symbol bar is stable, even if the ordering of the symbols is not.

Created by: codecov[bot]

Codecov Report

Merging #5511 into master will decrease coverage by 0.09%. The diff coverage is n/a.

@@            Coverage Diff            @@
##           master    #5511     +/-   ##
=========================================
- Coverage   47.03%   46.93%   -0.1%     
=========================================
  Files         741      739      -2     
  Lines       45428    45304    -124     
  Branches     2611     2604      -7     
=========================================
- Hits        21365    21265    -100     
+ Misses      21997    21981     -16     
+ Partials     2066     2058      -8

Impacted Files	Coverage Δ
web/src/search/helpers.tsx	30.3% <0%> (-23.7%)
cmd/frontend/graphqlbackend/graphqlbackend.go	57.89% <0%> (ø)
web/src/search/results/SearchResults.tsx	46.73% <0%> (ø)
web/src/search/results/SearchResultTypeTabs.tsx
pkg/a8n/store.go
web/src/search/results/SearchResultTab.tsx
cmd/frontend/db/campaigns.go	79.31% <0%> (ø)