Separate analysis from graph, esModuleFlag as analysis info

[guybedford]

This PR adds the following:

1. Separating the graph walking and file system calls from a "pure" analysis function in analysis.js.
2. The analysis function now returns { staticAssignmentNames, exportsAllFrom, esModuleFlag }, where exportsAllFrom are unresolved specifiers and esModuleFlag is a boolean indicating if an __esModule flag was set to truthy.
3. The default filtering is no longer included by default - rather it is down to the exact wrapper module implementation to handle this. In discussion with @jkrems we were able to come to a compromise that default should always be present on CommonJS module representations.