CI/Travis: restore ASAN build to first stage #10274

* ci: Travis: move ASAN build to first stage again
  Ref: https://github.com/neovim/neovim/pull/10238#issuecomment-503556762
* rename stages
* move gcov to second stage, restore order

.travis.yml

@@ -49,10 +49,14 @@ env:
 
 jobs:
   include:
-    - stage: baseline builds
+    - stage: baseline
       os: linux
-      compiler: gcc
-      env: GCOV=gcov CMAKE_FLAGS="$CMAKE_FLAGS -DUSE_GCOV=ON"
+      compiler: clang-4.0
+      # Use Lua so that ASAN can test our embedded Lua support. 8fec4d53d0f6
+      env: >
+        CLANG_SANITIZER=ASAN_UBSAN
+        CMAKE_FLAGS="$CMAKE_FLAGS -DPREFER_LUA=ON"
+        ASAN_SYMBOLIZE=asan_symbolize-4.0
     - os: linux
       compiler: gcc
       env: >
@@ -68,7 +72,7 @@ jobs:
       os: linux
       env: CI_TARGET=lint
 
-    - stage: Other builds
+    - stage: second stage
       os: osx
       compiler: clang
       osx_image: xcode10.1  # macOS 10.13
@@ -77,12 +81,8 @@ jobs:
       osx_image: xcode10.1  # macOS 10.13
 
     - os: linux
-      compiler: clang-4.0
-      # Use Lua so that ASAN can test our embedded Lua support. 8fec4d53d0f6
-      env: >
-        CLANG_SANITIZER=ASAN_UBSAN
-        CMAKE_FLAGS="$CMAKE_FLAGS -DPREFER_LUA=ON"
-        ASAN_SYMBOLIZE=asan_symbolize-4.0
+      compiler: gcc
+      env: GCOV=gcov CMAKE_FLAGS="$CMAKE_FLAGS -DUSE_GCOV=ON"
     - os: linux
       compiler: clang
       env: CLANG_SANITIZER=TSAN