get2byteNotZero() instead of get2byte() for the corner case where the
number cells is zero on a 65536-byte page.
FossilOrigin-Name: bcbe7d96df3c9515f679ccf671ca9ba89d081b53501495d4218eb5126196838b
if the database file is badly corrupted, to prevent warnings
from ASAN and valgrind.
FossilOrigin-Name: 65ad6c55f1ba9bc2f75afffa3adaf19f145fad7ac9a00ccce6372e9a2cc4341b
have been added to test/fuzzdata7.db, but have not yet all been fixed,
so tests will not currently pass.
FossilOrigin-Name: b4210d320c6426d2838d4cc08709fdfd015c1c95fcad9a5f9e8fd390c23b9fad
