[SYCL][API-break] Remove "using namespace experimental" inside ext::intel (#6415)

It had been deprecated before. I don't think it's an ABI break but it is
definitely an API break and we still need to increment major version in the next
release.

Author: aelovikov-intel

sycl/CMakeLists.txt

@@ -28,7 +28,7 @@ include(SYCLUtils)
 set(SYCL_MAJOR_VERSION 5)
 set(SYCL_MINOR_VERSION 7)
 set(SYCL_PATCH_VERSION 0)
-set(SYCL_DEV_ABI_VERSION 0)
+set(SYCL_DEV_ABI_VERSION 1)
 if (SYCL_ADD_DEV_VERSION_POSTFIX)
   set(SYCL_VERSION_POSTFIX "-${SYCL_DEV_ABI_VERSION}")
 endif()

sycl/include/sycl/ext/intel/experimental/online_compiler.hpp

@@ -219,13 +219,5 @@ online_compiler<source_language::cm>::compile(const std::string &src) {
 } // namespace experimental
 } // namespace intel
 } // namespace ext
-
-namespace ext {
-namespace __SYCL2020_DEPRECATED(
-    "use 'ext::intel::experimental' instead") intel {
-  using namespace ext::intel::experimental;
-} // namespace intel
-} // namespace ext
-
 } // namespace sycl
 } // __SYCL_INLINE_NAMESPACE(cl)

sycl/test/warnings/sycl_2020_deprecations.cpp

@@ -151,10 +151,6 @@ int main() {
   auto SL = sycl::INTEL::source_language::opencl_c;
   (void)SL;
 
-  // expected-warning@+1{{'intel' is deprecated: use 'ext::intel::experimental' instead}}
-  auto SLExtIntel = sycl::ext::intel::source_language::opencl_c;
-  (void)SLExtIntel;
-
   // expected-warning@+1{{'level_zero' is deprecated: use 'ext_oneapi_level_zero' instead}}
   auto LevelZeroBackend = sycl::backend::level_zero;
   (void)LevelZeroBackend;