Fix localAddress may be null,avoid throwing NullPointerException(#7621)

[skyguard1]

What is the purpose of the change

Fix localAddress may be null,and NullPointerException will be thrown in NetUtils
In this issue(#7621 ), this pr is to fix this issue, to avoid throwing NullPointerException in NetUtils, thanks

Brief changelog

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[codecov-commenter]

Codecov Report

Merging #7622 (1fbb870) into master (f8e25ec) will increase coverage by 0.03%.
The diff coverage is 66.66%.

@@             Coverage Diff              @@
##             master    #7622      +/-   ##
============================================
+ Coverage     59.11%   59.14%   +0.03%     
- Complexity      528      529       +1     
============================================
  Files          1076     1076              
  Lines         43443    43445       +2     
  Branches       6346     6347       +1     
============================================
+ Hits          25681    25697      +16     
+ Misses        14917    14916       -1     
+ Partials       2845     2832      -13     

Impacted Files	Coverage Δ	Complexity Δ
...n/java/org/apache/dubbo/common/utils/NetUtils.java	66.55% <66.66%> (-0.12%)	0.00 <0.00> (ø)
...ntext/event/AwaitingNonWebApplicationListener.java	48.48% <0.00%> (-24.25%)	0.00% <0.00%> (ø%)
...o/remoting/transport/ChannelHandlerDispatcher.java	60.00% <0.00%> (-10.00%)	0.00% <0.00%> (ø%)
...mmon/serialize/kryo/utils/AbstractKryoFactory.java	75.43% <0.00%> (-3.51%)	0.00% <0.00%> (ø%)
...e/dubbo/registry/integration/RegistryProtocol.java	57.94% <0.00%> (-2.81%)	0.00% <0.00%> (ø%)
...ting/exchange/support/header/HeartbeatHandler.java	90.69% <0.00%> (-2.33%)	0.00% <0.00%> (ø%)
...pache/dubbo/remoting/telnet/codec/TelnetCodec.java	50.61% <0.00%> (-0.62%)	0.00% <0.00%> (ø%)
...n/java/org/apache/dubbo/common/utils/UrlUtils.java	74.14% <0.00%> (-0.35%)	0.00% <0.00%> (ø%)
...he/dubbo/registry/multicast/MulticastRegistry.java	68.37% <0.00%> (ø)	0.00% <0.00%> (ø%)
...apache/dubbo/common/extension/ExtensionLoader.java	78.17% <0.00%> (+0.22%)	0.00% <0.00%> (ø%)
... and 18 more

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[xiaoheng1]

I checked the code. If LOCAL_ADDRESS is empty and throws an exception, the previous logic is changed: in the getLocalHost method, if LOCAL_ADDRESS is empty, it will return a LOCALHOST_VALUE.

[skyguard1]

But the return value of getLocalAddress method is localAddress, not LOCAL_ADDRESS, and getIpByHost(getLocalAddress().getHostName()) will be called in getIpByConfig(), and NullPointerException will be thrown here

[xiaoheng1]

But the return value of getLocalAddress method is localAddress, not LOCAL_ADDRESS, and getIpByHost(getLocalAddress().getHostName()) will be called in getIpByConfig(), and NullPointerException will be thrown here

1. The localAddress is assigned to LOCAL_ADDRESS, so it is the same.
2. My opinion is to make a non-empty judgment on getLocalAddress() in getIpByConfig.

[AlbumenJ]

LGTM.