OSV-2020-1319 Use-of-uninitialized-value in Interpreter::evaluate

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=15843 Crash type: Use-of-uninitialized-value Crash state: Interpreter::evaluate jsonnetvmexecute jsonnetevaluatesnippetaux...