Previously, we would not print out the .stack property of a SyntaxError,
but instead get its location from the .fileName, .lineNumber, and
.columnNumber properties.

This makes sense when assuming the SyntaxError arises from parsing a JS
file; there isn't anywhere the error is thrown from.
However, SyntaxErrors can actually be thrown from code: from JSON.parse(),
Reflect.parse(), and import(), to name a few examples. So we should print
out the stack trace if one is present.

Closes: #584