bugfix:fix auto proxying of datasource which has final modifier

[xingfudeshi]

Ⅰ. Describe what this PR did

When enable auto proxying of datasouce which has final modifier,it will cause a Exception means the class can't be proxied by using cglib.This PR will use JDK proxy instead of cglib to avoid this problem.

Ⅱ. Does this pull request fix one issue?

fixes #1995

Ⅲ. Why don't you add test cases (unit test/integration test)?

I've done integration testing with following scenes:
1.Specific init-method for a datasource bean defination.
2.A datasource class that with final modifier.
3.A datasource that extends AbstractRoutingDataSource.

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov-io]

Codecov Report

Merging #1996 into develop will increase coverage by 0.01%.
The diff coverage is 0%.

@@              Coverage Diff              @@
##             develop    #1996      +/-   ##
=============================================
+ Coverage      55.25%   55.26%   +0.01%     
- Complexity      2430     2432       +2     
=============================================
  Files            432      432              
  Lines          14439    14442       +3     
  Branches        1706     1706              
=============================================
+ Hits            7978     7982       +4     
- Misses          5736     5738       +2     
+ Partials         725      722       -3

Impacted Files	Coverage Δ	Complexity Δ
...ta/spring/annotation/GlobalTransactionScanner.java	48.67% <0%> (-1.33%)	17 <0> (ø)
...o/seata/server/coordinator/DefaultCoordinator.java	48.41% <0%> (+0.39%)	28% <0%> (+1%)	⬆️
...in/java/io/seata/server/session/GlobalSession.java	85.02% <0%> (+0.48%)	68% <0%> (+1%)	⬆️
...server/store/file/FileTransactionStoreManager.java	56.5% <0%> (+0.63%)	29% <0%> (ø)	⬇️

[slievrly]

LGTM

[zjinlei]

LGTM

[jsbxyyx]

LGTM