[dataview] Fix JSTests.json

This CL correctly updates the JSTests.json file in test/mjsunit/
to reflect the new DataView Float32/64 performance tests from
commit e14699c5.

Change-Id: I9cbb05ac0cbd37f8d8a0bc66ebb59c1e05298776
Reviewed-on: https://chromium-review.googlesource.com/1128880Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Commit-Queue: Théotime Grohens <theotime@google.com>
Cr-Commit-Position: refs/heads/master@{#54323}

test/js-perf-test/JSTests.json

@@ -488,8 +488,10 @@
       "tests": [
 	{"name": "DataViewTest-DataView-BigEndian"},
 	{"name": "DataViewTest-DataView-LittleEndian"},
+	{"name": "DataViewTest-DataView-Floats"},
 	{"name": "DataViewTest-TypedArray-BigEndian"},
-	{"name": "DataViewTest-TypedArray-LittleEndian"}
+	{"name": "DataViewTest-TypedArray-LittleEndian"},
+	{"name": "DataViewTest-TypedArray-Floats"}
       ]
     },
     {