[ptr-compr] Fix broken string externalization tests

... which will work for 32-bit kTaggedSize but we are not there yet.

Bug: v8:7703
Change-Id: Iaceb126ba316f37532221597cbd4f7e85ceb4fb9
Reviewed-on: https://chromium-review.googlesource.com/c/1482917Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59797}

test/cctest/test-api.cc

@@ -645,8 +645,10 @@ TEST(MakingExternalStringConditions) {
   // Old space strings should be accepted.
   CHECK(local_string->CanMakeExternal());
 
-  // Tiny strings are not in-place externalizable.
-  CHECK_EQ(!COMPRESS_POINTERS_BOOL, tiny_local_string->CanMakeExternal());
+  // Tiny strings are not in-place externalizable when pointer compression is
+  // enabled.
+  CHECK_EQ(i::kTaggedSize == i::kSystemPointerSize,
+           tiny_local_string->CanMakeExternal());
 }
 
 
@@ -668,8 +670,10 @@ TEST(MakingExternalOneByteStringConditions) {
   // Old space strings should be accepted.
   CHECK(local_string->CanMakeExternal());
 
-  // Tiny strings are not in-place externalizable.
-  CHECK_EQ(!COMPRESS_POINTERS_BOOL, tiny_local_string->CanMakeExternal());
+  // Tiny strings are not in-place externalizable when pointer compression is
+  // enabled.
+  CHECK_EQ(i::kTaggedSize == i::kSystemPointerSize,
+           tiny_local_string->CanMakeExternal());
 }