Omit some overenthusiastic file-truename calls

Omit some overenthusiastic file-truename calls

Problem reported by Tino Calancha (Bug#37445).
* src/emacs.c (init_cmdargs): Call file-truename only if
needed, i.e., if invocation-directory ends in "/i386/" on
WINDOWSNT.
* src/lread.c (readevalloop): If the sourcename is not
absolute, make it absolute.  There is no need to convert
non-absolute files into truenames, since absolute files are
not converted into truenames.
(init_lread): Do not convert source-directory into a truename
at startup.  There is no need to do so in a dumped Emacs since
an absolute file name suffices.  The source directory might
not even exist any more, or might have been replaced by an
interloper who takes advantage of the truename calculation.
(syms_of_lread): Remove Qfile_truename; no longer needed.