Change code coverage option name (#43999)

Summary:
According to [documentation](https://github.com/pytorch/pytorch/blob/master/tools/setup_helpers/cmake.py#L265), only options starts with `BUILD_` / `USE_` / `CMAKE_` in `CMakeLists.txt` can be imported by environment variables.

 ---
This diff is originally intended to enable  `c++` source coverage with `CircleCI` and `codecov.io`, but we will finish it in the future. You can find the related information in the diff history. Following is the originally procedur:

Based on [this pull request](https://github.com/pytorch/pytorch/commit/1bda5e480c0fe01dae8db718cd457befa1b46ac6), life becomes much easier for this time.
1.in `build.sh`
- Enable coverage builld option for c++
- `apt-get install lcov`

2.in `test.sh`
- run `lcov`

3.in `pytorch-job-specs.yml`
- copy coverage.info to `test/` folder and upload it to codecov.io

Pull Request resolved: https://github.com/pytorch/pytorch/pull/43999

Test Plan: Test on github

Reviewed By: malfet

Differential Revision: D23464656

Pulled By: scintiller

fbshipit-source-id: b2365691f04681d25ba5c00293fbcafe8e8e0745
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4c93504..248f741 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -144,7 +144,7 @@
 cmake_dependent_option(
     INSTALL_TEST "Install test binaries if BUILD_TEST is on" ON
     "BUILD_TEST" OFF)
-option(CODE_COVERAGE "Compile C/C++ with code coverage flags" OFF)
+option(USE_CPP_CODE_COVERAGE "Compile C/C++ with code coverage flags" OFF)
 option(COLORIZE_OUTPUT "Colorize output during compilation" ON)
 option(USE_ASAN "Use Address Sanitizer" OFF)
 option(USE_TSAN "Use Thread Sanitizer" OFF)
@@ -626,7 +626,7 @@
 
 
 # Add code coverage flags to supported compilers
-if(CODE_COVERAGE)
+if(USE_CPP_CODE_COVERAGE)
   if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
     string(APPEND CMAKE_C_FLAGS  " --coverage -fprofile-abs-path")
     string(APPEND CMAKE_CXX_FLAGS  " --coverage -fprofile-abs-path")
diff --git a/cmake/Summary.cmake b/cmake/Summary.cmake
index a2e6d63..3d4da7f 100644
--- a/cmake/Summary.cmake
+++ b/cmake/Summary.cmake
@@ -50,8 +50,8 @@
 
   message(STATUS "  INTERN_BUILD_MOBILE   : ${INTERN_BUILD_MOBILE}")
 
-  message(STATUS "  CODE_COVERAGE         : ${CODE_COVERAGE}")
   message(STATUS "  USE_ASAN              : ${USE_ASAN}")
+  message(STATUS "  USE_CPP_CODE_COVERAGE : ${USE_CPP_CODE_COVERAGE}")
   message(STATUS "  USE_CUDA              : ${USE_CUDA}")
   if(${USE_CUDA})
     message(STATUS "    CUDA static link    : ${CAFFE2_STATIC_LINK_CUDA}")