[release/8.0] [wasm] Endian fix for Webcil (#92495)

[release/8.0] [wasm] Endian fix for Webcil (#92495)

* [wasm] Endian fix for Webcil

'dotnet new blazorwasm' command failed on s390x and was throwing a not implemented exception

The issue was with with the WebCil writer and reader, specific endianness conversions relating to the webcil payload were not implemented for big endian machines.

We considered fixing the generic implementation, but there were only two structures in use: WebcilHeader and WebcilSectionHeader, so it was easier to handle them explicitly.

* Fix infinite recursion

* rename var

---------

Co-authored-by: Sanjam Panda <sanjam.panda@ibm.com>
Co-authored-by: Aleksey Kliger (λgeek) <alklig@microsoft.com>