修复在ParserConfig中指定String.class（及一些较基础类型class）的自定义反序列化器无效的问题

[Omega-Ariston]

修复 #2624 #1875 中提到的通过ParserConfig自定义反序列化String.class不起作用的问题。
根因是fastjson针对String.class， Long.class这类比较基础的类型做了优化，有提供默认的反序列化器，但在判断用户是否针对这些类型自定义了反序列化器的逻辑上有缺陷（只判断了通过注解指定的方式，而没有判断通过ParserConfig配置的方式）
这里在DefaultFieldDeserializer的构造函数中对ParserConfig中取出的反序列化器进行了额外判断，如果不是默认的反序列化器（而是用户自己定义的），则把DefaultFieldDeserializer.customDeserializer属性设置为true，触发使用自定义反序列化器的逻辑。而在此之前，用户只能通过注解的方式将这个属性设置为true。
为了判断当前反序列化器是否为默认反序列化器，在ParserConfig中存储了一个静态的Map，用于存储各个基础类型的默认反序列化器，方便进行比较。

[codecov-io]

Codecov Report

Merging #2670 into master will decrease coverage by 1.13%.
The diff coverage is 41.36%.

@@             Coverage Diff             @@
##             master   #2670      +/-   ##
===========================================
- Coverage     81.14%     80%   -1.14%     
- Complexity     7021    7059      +38     
===========================================
  Files           143     145       +2     
  Lines         26258   26713     +455     
  Branches       6276    6373      +97     
===========================================
+ Hits          21307   21373      +66     
- Misses         3129    3499     +370     
- Partials       1822    1841      +19

Impacted Files	Coverage Δ	Complexity Δ
...baba/fastjson/serializer/ASMSerializerFactory.java	96.05% <ø> (ø)	198 <0> (ø)	⬇️
...com/alibaba/fastjson/parser/JSONReaderScanner.java	72.61% <0%> (ø)	44 <2> (ø)	⬇️
...m/alibaba/fastjson/serializer/BigDecimalCodec.java	89.74% <0%> (ø)	18 <0> (ø)	⬇️
.../main/java/com/alibaba/fastjson/JSONValidator.java	0% <0%> (ø)	0 <0> (?)
...json/parser/deserializer/JavaBeanDeserializer.java	78.57% <100%> (+0.3%)	293 <0> (+2)	⬆️
...com/alibaba/fastjson/serializer/MapSerializer.java	75% <100%> (ø)	49 <0> (+1)	⬆️
.../main/java/com/alibaba/fastjson/util/ASMUtils.java	81.44% <100%> (-2.07%)	33 <0> (ø)
...fastjson/parser/deserializer/EnumDeserializer.java	90.32% <100%> (ø)	29 <0> (ø)	⬇️
src/main/java/com/alibaba/fastjson/JSONObject.java	86.05% <100%> (ø)	94 <0> (ø)	⬇️
...main/java/com/alibaba/fastjson/util/FieldInfo.java	86.94% <100%> (ø)	79 <0> (ø)	⬇️
... and 32 more

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[codecov-commenter]

Codecov Report

Merging #2670 into master will decrease coverage by 0.12%.
The diff coverage is 98.76%.

@@             Coverage Diff              @@
##             master    #2670      +/-   ##
============================================
- Coverage     80.13%   80.00%   -0.13%     
+ Complexity     7071     7059      -12     
============================================
  Files           145      145              
  Lines         26704    26713       +9     
  Branches       6372     6373       +1     
============================================
- Hits          21399    21373      -26     
- Misses         3473     3499      +26     
- Partials       1832     1841       +9     

Impacted Files	Coverage Δ	Complexity Δ
.../parser/deserializer/DefaultFieldDeserializer.java	87.50% <80.00%> (+0.73%)	24.00 <0.00> (+2.00)
...java/com/alibaba/fastjson/parser/ParserConfig.java	83.44% <100.00%> (-0.03%)	204.00 <4.00> (+1.00)	⬇️
...json/parser/deserializer/JavaBeanDeserializer.java	78.57% <100.00%> (-1.61%)	293.00 <0.00> (-7.00)
...ava/com/alibaba/fastjson/serializer/DateCodec.java	87.58% <0.00%> (-1.97%)	37.00% <0.00%> (-1.00%)
...com/alibaba/fastjson/parser/JSONReaderScanner.java	72.61% <0.00%> (-1.28%)	44.00% <0.00%> (-1.00%)
...ava/com/alibaba/fastjson/parser/JSONLexerBase.java	70.90% <0.00%> (-0.44%)	822.00% <0.00%> (-4.00%)
...n/java/com/alibaba/fastjson/util/JavaBeanInfo.java	87.88% <0.00%> (-0.19%)	197.00% <0.00%> (-1.00%)
...com/alibaba/fastjson/serializer/SerialContext.java	77.08% <0.00%> (+4.16%)	19.00% <0.00%> (ø%)

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[llsi4275]

@Omega-Ariston 在1.2.69+的版本中，这个全局的功能又失效了...
#3279