CI: re-enable gcc asan builds

for some unclear reasons asan builds were limited to clang only. let us
enable them for gcc as well

.github/matrix.py

@@ -57,7 +57,6 @@ def clean_compression(compression):
 
 
 def get_asan_flags(cc):
-    if cc == "clang":
     return [
         "USE_OBSOLETE_LINKER=1",
         'DEBUG_CFLAGS="-g -fsanitize=address"',
@@ -65,8 +64,6 @@ def get_asan_flags(cc):
         'CPU_CFLAGS.generic="-O1"',
     ]
 
-    raise ValueError("ASAN is only supported for clang")
-
 
 matrix = []
 
@@ -160,9 +157,9 @@ for CC in ["gcc", "clang"]:
 # ASAN
 
 os = "ubuntu-latest"
-CC = "clang"
 TARGET = "linux-glibc"
-matrix.append(
+for CC in ["gcc","clang"]:
+    matrix.append(
         {
             "name": "{}, {}, ASAN, all features".format(clean_os(os), CC),
             "os": os,
@@ -190,7 +187,7 @@ matrix.append(
                 "51DEGREES_SRC=addons/51degrees/dummy/pattern",
             ],
         }
-)
+    )
 
 # macOS