Kernel#eval: coerce parameter to string before doing anything else.
Kernel#eval: coerce parameter to string before doing anything else.

Previous behaviour was to delay it after storing/loading the object and
its context in a cache.
This could result in an implementation leak when passing an object
whose #hash method always returns nil (i.e. a NullObject).

pH14/rubinius,pH14/rubinius,dblock/rubinius,digitalextremist/rubinius,heftig/rubinius,ngpestelos/rubinius,jemc/rubinius,digitalextremist/rubinius,Azizou/rubinius,benlovell/rubinius,sferik/rubinius,ngpestelos/rubinius,jsyeo/rubinius,kachick/rubinius,ngpestelos/rubinius,ruipserra/rubinius,digitalextremist/rubinius,ngpestelos/rubinius,ngpestelos/rubinius,heftig/rubinius,benlovell/rubinius,Wirachmat/rubinius,mlarraz/rubinius,pH14/rubinius,heftig/rubinius,kachick/rubinius,Wirachmat/rubinius,mlarraz/rubinius,ruipserra/rubinius,jsyeo/rubinius,sferik/rubinius,mlarraz/rubinius,ngpestelos/rubinius,Azizou/rubinius,mlarraz/rubinius,pH14/rubinius,jsyeo/rubinius,jemc/rubinius,dblock/rubinius,Wirachmat/rubinius,Azizou/rubinius,kachick/rubinius,sferik/rubinius,heftig/rubinius,jemc/rubinius,pH14/rubinius,digitalextremist/rubinius,mlarraz/rubinius,pH14/rubinius,ngpestelos/rubinius,Wirachmat/rubinius,dblock/rubinius,Azizou/rubinius,kachick/rubinius,kachick/rubinius,dblock/rubinius,sferik/rubinius,sferik/rubinius,benlovell/rubinius,Azizou/rubinius,jemc/rubinius,heftig/rubinius,dblock/rubinius,ruipserra/rubinius,Azizou/rubinius,jemc/rubinius,ruipserra/rubinius,benlovell/rubinius,ruipserra/rubinius,benlovell/rubinius,jemc/rubinius,sferik/rubinius,jsyeo/rubinius,Azizou/rubinius,kachick/rubinius,mlarraz/rubinius,digitalextremist/rubinius,benlovell/rubinius,heftig/rubinius,jemc/rubinius,ruipserra/rubinius,kachick/rubinius,dblock/rubinius,jsyeo/rubinius,kachick/rubinius,heftig/rubinius,digitalextremist/rubinius,dblock/rubinius,Wirachmat/rubinius,benlovell/rubinius,jsyeo/rubinius,sferik/rubinius,jsyeo/rubinius,digitalextremist/rubinius,pH14/rubinius,mlarraz/rubinius,Wirachmat/rubinius,Wirachmat/rubinius,ruipserra/rubinius