[WIP] Sandbox Plugin Optimizations

[jacobgardner]

WIP: Still working through some optimizations and tests

Partial Fix of #190

Type of change

• Performance (a code change that improves performance)

For changes visible to end-users

• Suggested release notes are provided below:

Some performance optimizations to the esbuild bazel sandbox plugin

Test plan

• Covered by existing test cases

[jbedard]

Was there anything here you thought was worth investigating more?

[alexeagle]

Hi @jacobgardner I'm doing a bit of cleanup here, seems like this is probably abandoned. We'd still love to collaborate with you!