Let babel-jest handle loading babel config

[ahnpnl]

Closes #1341

Note: this needs to be well tested because it looks to me like a breaking change.

[coveralls]

Pull Request Test Coverage Report for Build 3951

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.2%) to 90.458%

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Totals
Change from base Build 3950:	0.2%
Covered Lines:	1066
Relevant Lines:	1122

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💛 - Coveralls

[kulshekhar]

This looks good to me. What problems do you anticipate with this change @ahnpnl ?

[ahnpnl]

we now only collect any babel configs we can and pass them to babel-jest invocation so I'm not sure if this might break anything, just that is my concern only.

[kulshekhar]

ok. Let's merge this in then. I'll push a new release later today after that

[ahnpnl]

ok let's proceed like that

[kulshekhar]

pushing a release out shortly.

aside: @ahnpnl when you get the chance, could you please check the message I've sent on slack?

[SimenB]

Yup, letting babel-jest handle all loading of babel config should be correct