devel/llvm10: fix the patch added in r552764

A stray semicolon would cause llvm binaries to segfault as they
always get the wrong "executable path" on 12.1/11.4. Only test built on
-CURRENT, which doesn't use this path. =(

Pointy hat: kevans
PR: 250478, 250448
MFH: 2020Q4 (implicit, build fix)