Target: Google Chrome for Testing 149.0.7827.115, Linux x64 headless-shell
Method: keep a packed-double array containing four distinctive 64-bit sentinel
values alive, attach GDB to the renderer, locate the contiguous sentinel in
writable heap memory, locate the JSArray whose compressed elements pointer
references that FixedDoubleArray, and read the JSArray header.

SENTINEL_DATA=0x35f5010473b0
FIXED_DOUBLE_ARRAY=0x010473a9
JSARRAY_OBJECT=0x35f501047381
JSARRAY_PROPERTIES=0x000007e5
CHROME_PACKED_DOUBLE_JSARRAY_MAP=0x010329bd
