Fix NPE in Http1ClientCodec

[minwoox]

Motivation:
If the remote peer sends multiple responses for one request, which is not allowed by the spec but may still be possible,
NPE can be raised in Http1ClientCodec.

Modification:

• Copy Http1ClientCodec from the upstream Netty 4.1.42 at 39cc7a673939dec96258ff27f5b1874671838af0

Result:

• No more NPE in Http1ClientCodec

[ikhoon]

Related: netty/netty#9465

[ikhoon]

Thanks @minwoox !

[codecov]

Codecov Report

Merging #2210 into master will decrease coverage by 0.02%.
The diff coverage is 18.18%.

@@             Coverage Diff              @@
##             master    #2210      +/-   ##
============================================
- Coverage     73.66%   73.64%   -0.03%     
- Complexity     9610     9614       +4     
============================================
  Files           839      839              
  Lines         37000    37001       +1     
  Branches       4557     4558       +1     
============================================
- Hits          27256    27249       -7     
- Misses         7418     7427       +9     
+ Partials       2326     2325       -1

Impacted Files	Coverage Δ	Complexity Δ
...om/linecorp/armeria/internal/Http1ClientCodec.java	48.27% <18.18%> (+0.6%)	6 <0> (ø)	⬇️
...om/linecorp/armeria/client/HttpSessionHandler.java	61.01% <0%> (-8.48%)	29% <0%> (-2%)
...meria/common/stream/RegularFixedStreamMessage.java	81.63% <0%> (-6.13%)	13% <0%> (-1%)
...necorp/armeria/server/GracefulShutdownSupport.java	97.43% <0%> (-2.57%)	4% <0%> (ø)
...a/com/linecorp/armeria/client/HttpChannelPool.java	72.76% <0%> (-2.34%)	59% <0%> (-2%)
...inecorp/armeria/server/grpc/ArmeriaServerCall.java	87.5% <0%> (+0.39%)	86% <0%> (+1%)	⬆️
...com/linecorp/armeria/server/HttpServerHandler.java	82.05% <0%> (+0.66%)	83% <0%> (+1%)	⬆️
...m/linecorp/armeria/client/HttpResponseDecoder.java	83.62% <0%> (+0.86%)	19% <0%> (ø)	⬇️
...inecorp/armeria/server/HttpResponseSubscriber.java	85.47% <0%> (+1.28%)	76% <0%> (+3%)	⬆️
.../com/linecorp/armeria/server/docs/ServiceInfo.java	80.7% <0%> (+1.75%)	21% <0%> (+1%)	⬆️
... and 1 more

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[minwoox]

Thanks for reviewing!