Bug fix in R2RDump signature decoder w.r.t. large version bubbles (dotnet/coreclr...

Bug fix in R2RDump signature decoder w.r.t. large version bubbles (dotnet/coreclr#24352)

JanV discovered a complex signature where the generic type argument
got decoded in an incorrect module context by R2RDump. Investigating
the issue I found out that the problem was caused by my slight
misunderstanding - all module override indices within a signature
are relative to the global signature context module, not to the current
context module that may change during descent into the signature tree.

Thanks

Tomas

Commit migrated from https://github.com/dotnet/coreclr/commit/1de8b99c660fdb0eab8688d16b7d77af6e362b56