AVA tests incompatible with Node 13

[fregante]

Node 13 supports ES Modules natively, but the esm package monkey patches ES Modules to CommonJS and causes Node to choke when it finds type: module in some dependencies.

This issue may depend on any of these:

• The ESM Plan avajs/ava#2293
• ts-node fails when ES Modules are in the dependency graph in Node.js 13+ TypeStrong/ts-node#935
• Error [ERR_REQUIRE_ESM]: Must use import to load ES Module / require() of ES modules is not supported standard-things/esm#868