Set the TSAN symbolizer path directly, the indirection via env doesn't work

.gitlab-ci.yml

@@ -18,7 +18,6 @@ variables:
   CONFIGURE: ./configure
   CLANG: clang-10
   SCAN_BUILD: scan-build-10
-  SYMBOLIZER: /usr/lib/llvm-10/bin/llvm-symbolizer
   ASAN_SYMBOLIZER_PATH: /usr/lib/llvm-10/bin/llvm-symbolizer
   CLANG_FORMAT: clang-format-10
 
@@ -26,7 +25,7 @@ variables:
 
   # Pass run-time flags to AddressSanitizer to get core dumps on error.
   ASAN_OPTIONS_COMMON: abort_on_error=1:disable_coredump=0:unmap_shadow_on_exit=1
-  TSAN_OPTIONS_COMMON: "second_deadlock_stack=1 history_size=7 log_exe_name=true log_path=tsan external_symbolizer_path=$SYMBOLIZER"
+  TSAN_OPTIONS_COMMON: "second_deadlock_stack=1 history_size=7 log_exe_name=true log_path=tsan external_symbolizer_path=/usr/lib/llvm-10/bin/llvm-symbolizer"
 
   TARBALL_EXTENSION: xz