[ptr-compr] Temporarily enable the turbo_decompression_elimination flag

Temporarily enable the flag to test the performance of the
DecompressionOptimization reducer.

Bug: v8:7703
Change-Id: Ia55d732a73f2aef7ef6e3da329c19b2752a41459
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1890091Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64642}

src/flags/flag-definitions.h

@@ -1519,7 +1519,7 @@ DEFINE_BOOL(interpreted_frames_native_stack, false,
 #endif
 
 // TODO(v8:9206, solanes): remove this when smi-corrupting reducer is fully on.
-DEFINE_BOOL_READONLY(turbo_decompression_elimination, true,
+DEFINE_BOOL_READONLY(turbo_decompression_elimination, false,
                      "enable the decompression elimination system when "
                      "pointer compression is enabled.")