Core: Fix wasm signature calculation (hopefully for good?) #1504

Job	Run time
Build Single-File Artifact (osx-x64, Cpp2IL)	51s
Build Single-File Artifact (linux-arm64, Cpp2IL)	53s
Build Single-File Artifact (win-x64, Cpp2IL)	57s
Build Single-File Artifact (osx-arm64, Cpp2IL)	52s
Build Single-File Artifact (win-arm64, Cpp2IL)	50s
Run Tests & Publish Dev Package	1m 59s
Build - Windows .NET Framework Zip	36s
Build Single-File Artifact (linux-x64, Cpp2IL)	52s
	7m 50s

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