Optimize the js package test by using compatibility mode base

[mstoykov]

For the most part most test execute extremely simple 1-2 line scripts which can be rewritten to not require babel or corejs and at this point run in compatibility-mode=base.

This shouldn't really be a problem for finding bugs in the extended mode, but maybe I am wrong.
As an example, I give TestVURunInterruptDoesntPanic, which is probably not the most representative, but still. The below are the first and second run of the same test (using -count):
without specifying compatibility-mode:base:

--- PASS: TestVURunInterruptDoesntPanic (13.89s)
    --- PASS: TestVURunInterruptDoesntPanic/Source (1.97s)
    --- PASS: TestVURunInterruptDoesntPanic/Archive (2.00s)
=== RUN   TestVURunInterruptDoesntPanic
=== RUN   TestVURunInterruptDoesntPanic/Source
=== RUN   TestVURunInterruptDoesntPanic/Archive
--- PASS: TestVURunInterruptDoesntPanic (4.93s)
    --- PASS: TestVURunInterruptDoesntPanic/Source (1.99s)
    --- PASS: TestVURunInterruptDoesntPanic/Archive (1.95s)

after speciying:

=== RUN   TestVURunInterruptDoesntPanic
=== RUN   TestVURunInterruptDoesntPanic/Source
=== RUN   TestVURunInterruptDoesntPanic/Archive
--- PASS: TestVURunInterruptDoesntPanic (3.48s)
    --- PASS: TestVURunInterruptDoesntPanic/Source (1.72s)
    --- PASS: TestVURunInterruptDoesntPanic/Archive (1.76s)
=== RUN   TestVURunInterruptDoesntPanic
=== RUN   TestVURunInterruptDoesntPanic/Source
=== RUN   TestVURunInterruptDoesntPanic/Archive
--- PASS: TestVURunInterruptDoesntPanic (3.55s)
    --- PASS: TestVURunInterruptDoesntPanic/Source (1.75s)
    --- PASS: TestVURunInterruptDoesntPanic/Archive (1.79s)

as you can see the difference is signifacant as the parsing of the code apperantly takes 10.5s more without specifying base and the execution combined takes like 0.5s less (the number vary but not more then 0.1s in my experiments).

All of the above is ran with -race and the code change is:

diff --git a/js/runner_test.go b/js/runner_test.go
index 15d24d1d..350db362 100644
--- a/js/runner_test.go
+++ b/js/runner_test.go
@@ -584,13 +584,15 @@ func TestVURunInterruptDoesntPanic(t *testing.T) {
                t.Skip()
        }

-       r1, err := getSimpleRunner("/script.js", `
-               export default function() { while(true) {} }
-               `)
+       rtOpts := lib.RuntimeOptions{CompatibilityMode: null.StringFrom("base")}
+       r1, err := getSimpleRunnerWithOptions("/script.js", `
+               exports.default = function() { while(true) {} }
+               `, rtOpts)
+
        require.NoError(t, err)
        require.NoError(t, r1.SetOptions(lib.Options{Throw: null.BoolFrom(true)}))

-       r2, err := NewFromArchive(r1.MakeArchive(), lib.RuntimeOptions{})
+       r2, err := NewFromArchive(r1.MakeArchive(), rtOpts)
        require.NoError(t, err)
        testdata := map[string]*Runner{"Source": r1, "Archive": r2}
        for name, r := range testdata {

[mstoykov]

This was done by #1429