Fix flaky test JSONPath_reverse_test

[MengdiGao]

Existing test is flaky because it relies on the ordering of elements in a map. To fix it, use SerializerFeature.MapSortField to force ordering when convert JSON to string, but the MapSortField config does not apply to list elements, so I manually compare all permutations of list elements.

The flaky test was found by running NonDex (https://github.com/TestingResearchIllinois/NonDex).

[codecov-io]

Codecov Report

Merging #3530 (133cca0) into master (8124e5e) will decrease coverage by 0.07%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #3530      +/-   ##
============================================
- Coverage     80.46%   80.38%   -0.08%     
+ Complexity     7488     7486       -2     
============================================
  Files           157      157              
  Lines         27915    27929      +14     
  Branches       6731     6737       +6     
============================================
- Hits          22461    22452       -9     
- Misses         3445     3466      +21     
- Partials       2009     2011       +2     

Impacted Files	Coverage Δ	Complexity Δ
...com/alibaba/fastjson/serializer/SerialContext.java	82.69% <0.00%> (-3.85%)	21.00% <0.00%> (-1.00%)
...com/alibaba/fastjson/parser/JSONReaderScanner.java	73.58% <0.00%> (-1.26%)	45.00% <0.00%> (-1.00%)
...main/java/com/alibaba/fastjson/util/FieldInfo.java	85.76% <0.00%> (-1.00%)	96.00% <0.00%> (-3.00%)
src/main/java/com/alibaba/fastjson/JSONPath.java	75.32% <0.00%> (-0.49%)	275.00% <0.00%> (ø%)
...main/java/com/alibaba/fastjson/util/TypeUtils.java	79.21% <0.00%> (-0.12%)	654.00% <0.00%> (ø%)
...ain/java/com/alibaba/fastjson/asm/ClassReader.java	87.23% <0.00%> (-0.07%)	44.00% <0.00%> (ø%)
.../main/java/com/alibaba/fastjson/JSONValidator.java	64.72% <0.00%> (+0.34%)	56.00% <0.00%> (+1.00%)

---

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 8124e5e...133cca0. Read the comment docs.