[browser] host improvements

[pavelsavara]

Filesystem

• simplified coreRun to never exit
• replace cwd() in coreRun to pretend that NODERAWFS on Windows is Unix
• introduce browserVirtualAppBase constant(s) and unify the app directory to /managed.
  • for Mono too!
• make virtual path of VFS resources in the loader config relative to browserVirtualAppBase, unless explicitly absolute. WasmFilesToIncludeInFileSystem
• use browserVirtualAppBase for TPA
• create virtualWorkingDirectory and change current directory to it

Fail fast

• always assert and fail PortableEntryPoint::GetActualCode if the function is NULL
• detect attached debugger. Kill the process if it is not attached, like int3 does elsewhere
• quit on V8
• wrap all timers with catch -> abort
• abortPosix implemented as emscripten ___trap(), so that we don't run C++ finalizers on exit()

Other

• implement PAL_ProbeMemory for browser
• -sALLOW_TABLE_GROWTH=1 for R2R
• move some code to browserhost/host/assets.ts
• trim sockets
• feedback from [browser][coreCLR] node and v8 CLI support for default browser runtime #123501
  • drop support for CLI self-configuration on NodeJS
  • globalThisAny
  • code formating
• make browserHost to run on V8/D8 shell
  • optional TextDecoder

[dotnet-policy-service]

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