Segmentation fault on some gerund arguments to ^:

[mlochbaum]

Executing the following yields a segfault with any string in place of 'string':

]^:(1:`(<,'0';'string')) 0

[iocane]

Another missing type test when recovering the verbs from a gerund. The curious thing about this one is that I could not find any test coverage for ^: with gerund right arguments. Fixed in commit 41c629f.