Reverse the order of db queries in GetActionsByIndex API

[lizhefeng]

#1185

[codecov]

Codecov Report

Merging #1196 into master will increase coverage by 0.07%.
The diff coverage is 93.1%.

@@            Coverage Diff             @@
##           master    #1196      +/-   ##
==========================================
+ Coverage   54.26%   54.34%   +0.07%     
==========================================
  Files         155      155              
  Lines       12488    12512      +24     
==========================================
+ Hits         6777     6800      +23     
- Misses       4876     4877       +1     
  Partials      835      835

Impacted Files	Coverage Δ
api/api.go	64.32% <93.1%> (+0.97%)	⬆️
db/trie/extensionnode.go	59.32% <0%> (+1.69%)	⬆️

---

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[codecov]

Codecov Report

Merging #1196 into master will increase coverage by 0.07%.
The diff coverage is 93.1%.

@@            Coverage Diff             @@
##           master    #1196      +/-   ##
==========================================
+ Coverage   54.26%   54.34%   +0.07%     
==========================================
  Files         155      155              
  Lines       12488    12512      +24     
==========================================
+ Hits         6777     6800      +23     
- Misses       4876     4877       +1     
  Partials      835      835

Impacted Files	Coverage Δ
api/api.go	64.32% <93.1%> (+0.97%)	⬆️
db/trie/extensionnode.go	59.32% <0%> (+1.69%)	⬆️

---

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 ed2c73a...860b2d8. Read the comment docs.

[codecov]

Codecov Report

Merging #1196 into master will increase coverage by 0.06%.
The diff coverage is 93.54%.

@@            Coverage Diff             @@
##           master    #1196      +/-   ##
==========================================
+ Coverage   54.26%   54.33%   +0.06%     
==========================================
  Files         155      155              
  Lines       12488    12513      +25     
==========================================
+ Hits         6777     6799      +22     
- Misses       4876     4878       +2     
- Partials      835      836       +1

Impacted Files	Coverage Δ
api/api.go	64.38% <93.54%> (+1.03%)	⬆️

---

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Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ed2c73a...84f84b7. Read the comment docs.

[zjshen14]

@puncsky pls take a look it make sense to mitigate the issue for iotexscan. Thanks