ectest: fix warnings about precedence
ectest: fix warnings about precedence

This also fixes a bug since & has lower precedence than ==, the expression
"rand() & 7 == 0" was actually busted before this.

xiphmont/daala,HeadhunterXamd/daala,xiphmont/daala,KyleSiefring/daala,xiphmont/daala,HeadhunterXamd/daala,HeadhunterXamd/daala,ycho/daala,luctrudeau/daala,KyleSiefring/daala,ycho/daala,ycho/daala,xiph/daala,HeadhunterXamd/daala,xiph/daala,jmvalin/daala,KyleSiefring/daala,xiph/daala,luctrudeau/daala,luctrudeau/daala,KyleSiefring/daala,xiph/daala,ycho/daala,xiphmont/daala,luctrudeau/daala,ycho/daala,jmvalin/daala,jmvalin/daala,HeadhunterXamd/daala,xiph/daala,xiphmont/daala,jmvalin/daala,luctrudeau/daala,KyleSiefring/daala,jmvalin/daala