runtime: fix UAF from spad lifetime mismatch in prepare_and_execute_txn

[two-heart]

fd_runtime_prepare_and_execute_txn wrapped allocations in an internal FD_SPAD_FRAME, so allocations like rollback fee payer were freed before fd_runtime_finalize_txn consumed them

[two-heart]

ASAN report from executing block level fixtures with deep asan:

=================================================================
==993616==ERROR: AddressSanitizer: use-after-poison on address 0x6e9b70896350 at pc 0x5d720f4b5ef2 bp 0x7ffec8bee670 sp 0x7ffec8be
e668
READ of size 8 at 0x6e9b70896350 thread T0
    #0 0x5d720f4b5ef1 in fd_hashes_account_lthash /home/liam/firedancer/src/flamenco/runtime/fd_hashes.c:20:7
    #1 0x5d720f4b8b6f in fd_hashes_update_lthash /home/liam/firedancer/src/flamenco/runtime/fd_hashes.c:75:3
    #2 0x5d720f4ebdf1 in fd_runtime_save_account /home/liam/firedancer/src/flamenco/runtime/fd_runtime.c:1074:3
    #3 0x5d720f4eb487 in fd_runtime_finalize_txn /home/liam/firedancer/src/flamenco/runtime/fd_runtime.c:1126:7
    #4 0x5d720f39ea35 in fd_runtime_fuzz_block_ctx_exec /home/liam/firedancer/src/flamenco/runtime/tests/fd_block_harness.c:493:7
    #5 0x5d720f39ea35 in fd_solfuzz_block_run /home/liam/firedancer/src/flamenco/runtime/tests/fd_block_harness.c:536:15
    #6 0x5d720f39313b in fd_solfuzz_execute_wrapper /home/liam/firedancer/src/flamenco/runtime/tests/fd_solfuzz_private.h:55:20
    #7 0x5d720f39313b in fd_solfuzz_block_fixture /home/liam/firedancer/src/flamenco/runtime/tests/fd_solfuzz_exec.c:316:3
    #8 0x5d720f38f7dc in run_test1 /home/liam/firedancer/src/flamenco/runtime/tests/test_sol_compat.c:66:10
    #9 0x5d720f38f7dc in run_test /home/liam/firedancer/src/flamenco/runtime/tests/test_sol_compat.c:84:14
    #10 0x5d720f38efc8 in visit_sync /home/liam/firedancer/src/flamenco/runtime/tests/test_sol_compat.c:192:12
    #11 0x5d720f38f2bb in recursive_walk1 /home/liam/firedancer/src/flamenco/runtime/tests/test_sol_compat.c:143:12
    #12 0x5d720f38edfc in recursive_walk /home/liam/firedancer/src/flamenco/runtime/tests/test_sol_compat.c:179:12
    #13 0x5d720f38e4c3 in run_single_threaded /home/liam/firedancer/src/flamenco/runtime/tests/test_sol_compat.c:205:14
    #14 0x5d720f38e4c3 in main /home/liam/firedancer/src/flamenco/runtime/tests/test_sol_compat.c:460:5
    #15 0x73f2eb42a1c9 in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
    #16 0x73f2eb42a28a in __libc_start_main csu/../csu/libc-start.c:360:3
    #17 0x5d720f2b2724 in _start (/home/liam/firedancer/build/linux/clang/icelake/unit-test/test_sol_compat+0xc2724) (BuildId: bdb
bf48b009c58d4cd49dec95d8741aef5e8f65f)

Address 0x6e9b70896350 is a wild pointer inside of access range of size 0x000000000008.
SUMMARY: AddressSanitizer: use-after-poison /home/liam/firedancer/src/flamenco/runtime/fd_hashes.c:20:7 in fd_hashes_account_lthas
h
Shadow bytes around the buggy address:
  0x6e9b70896080: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
  0x6e9b70896100: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
  0x6e9b70896180: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
  0x6e9b70896200: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
  0x6e9b70896280: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
=>0x6e9b70896300: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7[f7]f7 f7 f7 f7 f7
  0x6e9b70896380: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
  0x6e9b70896400: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
  0x6e9b70896480: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
  0x6e9b70896500: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
  0x6e9b70896580: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
==993616==ABORTING