For some reason, the unit tests for Deno.remove() were not being imported to
unit_tests.ts and, consequently, not being executed. Thus, I imported them,
refactored some existent ones and wrote new ones for the symlink removal case.
Since the creation of a symlink is not implemented for Windows yet, assertions
that consider this state were added when the tests are executed in this OS.
This flag was added to evaluate performance relative to tokio's threaded
runtime. Although it's faster in the HTTP benchmark, it's clear the runtime
is not the only perf problem.
Removing this flag will simplify further refactors, in particular
adopting the #[tokio::main] macro. This will be done in a follow up.
Ultimately we expect to move to the current thread runtime with Isolates
pinned to specific threads, but that will be a much larger refactor. The
--current-thread just complicates that effort.
Before:
```
▶ target/debug/deno https://deno.land/std/examples/echo_server.ts
error: Uncaught PermissionDenied: run again with the --allow-net flag
► $deno$/dispatch_json.ts:40:11
at DenoError ($deno$/errors.ts:20:5)
at unwrapResponse ($deno$/dispatch_json.ts:40:11)
at sendSync ($deno$/dispatch_json.ts:67:10)
at listen ($deno$/net.ts:170:15)
at https://deno.land/std/examples/echo_server.ts:4:23
```
```
▶ target/debug/deno --allow-read=/usr https://deno.land/std/examples/cat.ts /etc/passwd
error: Uncaught PermissionDenied: run again with the --allow-read flag
► $deno$/dispatch_json.ts:40:11
at DenoError ($deno$/errors.ts:20:5)
at unwrapResponse ($deno$/dispatch_json.ts:40:11)
at sendAsync ($deno$/dispatch_json.ts:91:10)
```
After:
```
▶ target/debug/deno https://deno.land/std/examples/echo_server.ts
error: Uncaught PermissionDenied: network access to "0.0.0.0:8080", run again with the --allow-net flag
► $deno$/dispatch_json.ts:40:11
at DenoError ($deno$/errors.ts:20:5)
at unwrapResponse ($deno$/dispatch_json.ts:40:11)
at sendSync ($deno$/dispatch_json.ts:67:10)
at listen ($deno$/net.ts:170:15)
at https://deno.land/std/examples/echo_server.ts:4:23
```
```
▶ target/debug/deno --allow-read=/usr https://deno.land/std/examples/cat.ts /etc/passwd
error: Uncaught PermissionDenied: read access to "/etc/passwd", run again with the --allow-read flag
► $deno$/dispatch_json.ts:40:11
at DenoError ($deno$/errors.ts:20:5)
at unwrapResponse ($deno$/dispatch_json.ts:40:11)
at sendAsync ($deno$/dispatch_json.ts:91:10)
```
* move is_dyn_import argument from Loader::resolve to Loader::load - it was always kind of strange that resolve() checks permissions.
* change argument type from &str to &ModuleSpecifier where applicable
