CI: github: remove redundant ASAN loop

it was there because we only ran ASAN for clang, now no need to separate loop

Can be backported to 2.6.
diff --git a/.github/matrix.py b/.github/matrix.py
index fd9491a..93ecd3c 100755
--- a/.github/matrix.py
+++ b/.github/matrix.py
@@ -112,6 +112,38 @@
         }
     )
 
+# ASAN
+
+    matrix.append(
+        {
+            "name": "{}, {}, ASAN, all features".format(clean_os(os), CC),
+            "os": os,
+            "TARGET": TARGET,
+            "CC": CC,
+            "FLAGS": get_asan_flags(CC)
+            + [
+                "USE_ZLIB=1",
+                "USE_OT=1",
+                "OT_INC=${HOME}/opt-ot/include",
+                "OT_LIB=${HOME}/opt-ot/lib",
+                "OT_RUNPATH=1",
+                "USE_PCRE=1",
+                "USE_PCRE_JIT=1",
+                "USE_LUA=1",
+                "USE_OPENSSL=1",
+                "USE_SYSTEMD=1",
+                "USE_WURFL=1",
+                "WURFL_INC=addons/wurfl/dummy",
+                "WURFL_LIB=addons/wurfl/dummy",
+                "USE_DEVICEATLAS=1",
+                "DEVICEATLAS_SRC=addons/deviceatlas/dummy",
+                "USE_PROMEX=1",
+                "USE_51DEGREES=1",
+                "51DEGREES_SRC=addons/51degrees/dummy/pattern",
+            ],
+        }
+    )
+
     for compression in ["USE_ZLIB=1"]:
         matrix.append(
             {
@@ -154,41 +186,6 @@
             }
         )
 
-# ASAN
-
-os = "ubuntu-latest"
-TARGET = "linux-glibc"
-for CC in ["gcc","clang"]:
-    matrix.append(
-        {
-            "name": "{}, {}, ASAN, all features".format(clean_os(os), CC),
-            "os": os,
-            "TARGET": TARGET,
-            "CC": CC,
-            "FLAGS": get_asan_flags(CC)
-            + [
-                "USE_ZLIB=1",
-                "USE_OT=1",
-                "OT_INC=${HOME}/opt-ot/include",
-                "OT_LIB=${HOME}/opt-ot/lib",
-                "OT_RUNPATH=1",
-                "USE_PCRE=1",
-                "USE_PCRE_JIT=1",
-                "USE_LUA=1",
-                "USE_OPENSSL=1",
-                "USE_SYSTEMD=1",
-                "USE_WURFL=1",
-                "WURFL_INC=addons/wurfl/dummy",
-                "WURFL_LIB=addons/wurfl/dummy",
-                "USE_DEVICEATLAS=1",
-                "DEVICEATLAS_SRC=addons/deviceatlas/dummy",
-                "USE_PROMEX=1",
-                "USE_51DEGREES=1",
-                "51DEGREES_SRC=addons/51degrees/dummy/pattern",
-            ],
-        }
-    )
-
 # macOS
 
 os = "macos-latest"