Kpm pack generate bash scripts

parent #327 
For each KRE to be tested, we create a unique KRE home path for it. For example, for a local build of KRE version 1.0.0, the following 4 KRE homes are generated by test utils:
`<TempDir1>\packages\KRE-CLR-x86.1.0.0`
`<TempDir2>\packages\KRE-CLR-amd64.1.0.0`
`<TempDir3>\packages\KRE-CoreCLR-x86.1.0.0`
`<TempDir4>\packages\KRE-CoreCLR-amd64.1.0.0`

This line is used to get root path of the KRE we are currently testing against,