Copy chisel3.stage.ChiselStageSpec tests for CIRCT (#3019)

Copy relevant tests about chisel3.stage.ChiselStageSpec into
circt.stage.ChiselStageSpec.  This covers cases related to exception
handling and error reporting.  All other tests are already duplicated.

This is done in preparation to remove chisel3.stage.ChiselStage on the chisel5
branch. (!!!)

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>