[roottest] use fixture in root/meta/tclass/regression

On the Windows one should compile macro before running it,
for simplicity does it on all platforms.

Change test names to avoid collision in log files
Remove unused files

Author: linev

roottest/root/meta/tclass/regression/.rootrc

@@ -6,27 +6,26 @@ ROOTTEST_ADD_TEST(execNormalizationInf
                   MACRO execNormalizationInf.C
                   OUTREF execNormalizationInf.ref)
 
-if(ROOT_pyroot_FOUND)
+if(pyroot)
     ROOTTEST_ADD_TEST(execNormalizationInfPy
                   MACRO execNormalizationInf.py
                   OUTREF execNormalizationInf.py.ref
                   ENVIRONMENT CLING_STANDARD_PCH=none
                   CPPYY_BACKEND_LIBRARY=${CMAKE_BINARY_DIR}/lib/libcppyy_backend.so)
 endif()
 
-ROOTTEST_ADD_TEST(execROOT_6038
+ROOTTEST_ADD_TEST(6038
                   MACRO execROOT_6038.C
                   OUTREF execROOT_6038.ref)
 
-ROOTTEST_ADD_TEST(execROOT_6019
+ROOTTEST_ADD_TEST(6019
                   MACRO execROOT_6019.C
                   OUTREF execROOT_6019.ref)
 
-if(MSVC)
-    # needed on Windows to prevent having to run the test twice
-    # the first time being always failing and successful the second time
-    ROOTTEST_COMPILE_MACRO(execROOT_6277.cxx)
-endif()
-ROOTTEST_ADD_TEST(execROOT_6277
+ROOTTEST_COMPILE_MACRO(execROOT_6277.cxx
+                       FIXTURES_SETUP root-meta-tclass-regression-6277-fixture)
+
+ROOTTEST_ADD_TEST(6277
                   MACRO execROOT_6277.cxx+
-                  OUTREF execROOT_6277.ref)
+                  OUTREF execROOT_6277.ref
+                  FIXTURES_REQUIRED root-meta-tclass-regression-6277-fixture)