Fix: struct2MapAll logics

[justxuewei]

What this PR does:

• Fix: struct2mapAll couldn't handle with complicated struct.(same with Fix: Map generalization bug for generic filter #1354)
• Fix: Size computation for allocation may overflow

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[codecov-commenter]

Codecov Report

Merging #1356 (6ab300a) into 1.5 (467c867) will increase coverage by 0.48%.
The diff coverage is 67.22%.

❗ Current head 6ab300a differs from pull request most recent head ef04f90. Consider uploading reports for the commit ef04f90 to get more accurate results

@@            Coverage Diff             @@
##              1.5    #1356      +/-   ##
==========================================
+ Coverage   58.07%   58.56%   +0.48%     
==========================================
  Files         275      282       +7     
  Lines       13381    16335    +2954     
==========================================
+ Hits         7771     9566    +1795     
- Misses       4650     5771    +1121     
- Partials      960      998      +38     

Impacted Files	Coverage Δ
config/config_loader.go	43.40% <0.00%> (+4.56%)	⬆️
config/provider_config.go	62.06% <0.00%> (+7.52%)	⬆️
config/reference_config.go	80.00% <0.00%> (-1.67%)	⬇️
remoting/zookeeper/listener.go	42.79% <0.00%> (+1.51%)	⬆️
config/config_center_config.go	66.21% <33.33%> (+2.03%)	⬆️
registry/directory/directory.go	77.89% <58.33%> (+2.14%)	⬆️
protocol/dubbo/dubbo_invoker.go	70.29% <60.00%> (+0.97%)	⬆️
filter/filter_impl/generic_filter.go	62.50% <65.38%> (-8.72%)	⬇️
protocol/grpc/server.go	77.14% <66.66%> (+3.80%)	⬆️
registry/etcdv3/listener.go	74.00% <71.42%> (+6.50%)	⬆️
... and 291 more

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