enable test for react tsx sourcemaps

[cspotcode]

I kept seeing this test disables, so I enabled it. I don't know if it was meant to test something else.

[codecov]

Codecov Report

Merging #1088 into master will not change coverage.
The diff coverage is n/a.

@@ Coverage Diff @@## master #1088 +/- ##
=======================================
Coverage 75.08% 75.08% =======================================
Files 6 6 Lines 606 606 Branches 141 141 =======================================
Hits 455 455 Misses 100 100 Partials 51 51 

Flag	Coverage Δ
#node_10	72.15% <ø> (-0.20%)	⬇️
#node_12_15	72.74% <ø> (ø)
#node_12_16	72.74% <ø> (ø)
#node_13	74.58% <ø> (-0.17%)	⬇️
#node_14	74.75% <ø> (-0.17%)	⬇️
#typescript_2_7	74.58% <ø> (ø)
#typescript_latest	73.76% <ø> (ø)
#typescript_next	73.59% <ø> (ø)
#ubuntu	74.58% <ø> (-0.17%)	⬇️
#windows	74.91% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update cc364bf...1cae13a. Read the comment docs.

[coveralls]

Coverage increased (+1.03%) to 82.99% when pulling 1cae13a on ab/enable-react-tsx-sourcemap-test into b3f84bc on master.