Test suite fails

On a fresh install:

```bash
julian@Julians-MBP node-gently % make test
node test/simple/test-gently.js
node:assert:122
throw new AssertionError(obj);
^

AssertionError [ERR_ASSERTION]: '[Foo].bar()' == '[object Object].bar()'
at testUnamedClass (/Users/julian/dev/juliangruber/node-gently/test/simple/test-gently.js:324:12)
at _name (/Users/julian/dev/juliangruber/node-gently/test/simple/test-gently.js:325:5)
at test (/Users/julian/dev/juliangruber/node-gently/test/simple/test-gently.js:8:3)
at Object. (/Users/julian/dev/juliangruber/node-gently/test/simple/test-gently.js:305:1)
at Module._compile (node:internal/modules/cjs/loader:1091:14)
at Object.Module._extensions..js (node:internal/modules/cjs/loader:1120:10)
at Module.load (node:internal/modules/cjs/loader:971:32)
at Function.Module._load (node:internal/modules/cjs/loader:812:14)
at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:76:12)
at node:internal/main/run_main_module:17:47 {
generatedMessage: true,
code: 'ERR_ASSERTION',
actual: '[Foo].bar()',
expected: '[object Object].bar()',
operator: '=='
}
make: *** [test] Error 1
julian@Julians-MBP node-gently % node -v
v15.9.0
```