Reorganize tests; camelCase plugin name

test/fixtures/experimental/decorators-stage-2/computed-member-expr-on-prop/options.json

@@ -1,4 +1,4 @@
 {
-  "plugins": ["decorators-stage-2", "classProperties"],
+  "plugins": ["decoratorsStage2", "classProperties"],
   "throws": "Unexpected token (2:12)"
 }

test/fixtures/experimental/decorators-stage-2/computed-member-expression/options.json

@@ -1,4 +1,4 @@
 {
-  "plugins": ["decorators-stage-2", "classProperties"],
+  "plugins": ["decoratorsStage2", "classProperties"],
   "throws": "Stage 2 decorators may only be used with a class or a class method (2:6)"
 }

test/fixtures/experimental/decorators-stage-2/no-computed-name-prop/options.json

@@ -1,4 +1,4 @@
 {
-  "plugins": ["classProperties", "decorators-stage-2"],
+  "plugins": ["classProperties", "decoratorsStage2"],
   "throws": "Stage 2 decorators may only be used with a class or a class method (2:7)"
 }

test/fixtures/experimental/decorators-stage-2/options.json

@@ -1,3 +1,3 @@
 {
-  "plugins": ["decorators-stage-2"]
+  "plugins": ["decoratorsStage2"]
 }