[MERGE #596] Jenkins: Remove requirement of branch-specific task configuration to unblock CI on `linux` and `WebAssembly` branches.
[MERGE #596] Jenkins: Remove requirement of branch-specific task configuration to unblock CI on `linux` and `WebAssembly` branches.

Merge pull request #596 from dilijev:unbranchify

Microsoft/ChakraCore,mrkmarron/ChakraCore,Microsoft/ChakraCore,mrkmarron/ChakraCore,mrkmarron/ChakraCore,Microsoft/ChakraCore,Microsoft/ChakraCore,mrkmarron/ChakraCore,Microsoft/ChakraCore,mrkmarron/ChakraCore,Microsoft/ChakraCore,mrkmarron/ChakraCore,mrkmarron/ChakraCore