Fix request header capture corrupting tomcat request

[laurit]

Hopefully resolves #11464
Related to #6766
Avoid calling toString on MessageBytes and use messageBytesToString instead as was done in #6766 for other places.
I wasn't able to figure out how exactly reading headers manages to corrupt other parts of the request (there seems to be shared buffer, part of which gets overwritten so request uri starts returning an unexpected result). I believe that this can only be reproduced with some versions of tomcat (test app uses 10.1.5). #6766 mentions that the issue was introduced in 10.1.0 but was later backported to earlier versions. Latest version does not seem to contain the problematic code any more.

[pepeshore]

Calling toString will execute the code in the screenshot below which will overwrite a globle buffer。

The code above was introduced in Tomcat version 10.1.0 and fixed in version 10.1.6, fixed code is below

It seems to be a tomcat bug, but does it a good choice to read header in @Advice.OnMethodEnter of Tomcat method org.apache.catalina.connector.CoyoteAdapter.service

I notice that postParseRequest is called in org.apache.catalina.connector.CoyoteAdapter.service, It means that the request is not ready? so we should not reader header here?