[libc] Disable block test on NVPTX

Summary:
We already disable the freelist, the block test also causes issues. We
don't use this code at all on the GPU so we can disable this test for
now.

libc/test/src/__support/CMakeLists.txt

@@ -1,20 +1,20 @@
 add_custom_target(libc-support-tests)
 
-add_libc_test(
-  block_test
-  SUITE
-    libc-support-tests
-  SRCS
-    block_test.cpp
-  DEPENDS
-    libc.src.__support.CPP.array
-    libc.src.__support.CPP.bit
-    libc.src.__support.CPP.span
-    libc.src.__support.block
-    libc.src.string.memcpy
-)
-
 if(NOT LIBC_TARGET_ARCHITECTURE_IS_NVPTX)
+  add_libc_test(
+    block_test
+    SUITE
+      libc-support-tests
+    SRCS
+      block_test.cpp
+    DEPENDS
+      libc.src.__support.CPP.array
+      libc.src.__support.CPP.bit
+      libc.src.__support.CPP.span
+      libc.src.__support.block
+      libc.src.string.memcpy
+  )
+
   add_libc_test(
     freelist_test
     SUITE