fix: if/else case with no dependencies

[J-IN]

Related to : #3505

Adds an additional check to #3478 to deal with this case :

{#if "Eva".startsWith('E')}
eee
{:else}
rrr
{/if}

that generate this code :

if ((show_if == null) || ) show_if = !!("Eva".startsWith('E') == true)

This fix now generate the following when there are no dependencies :

if ((show_if == null) || false) show_if = !!("Eva".startsWith('E') == true)

[codecov-io]

Codecov Report

Merging #3514 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #3514   +/-   ##
=======================================
  Coverage   50.25%   50.25%           
=======================================
  Files           1        1           
  Lines         197      197           
=======================================
  Hits           99       99           
  Misses         98       98

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[Rich-Harris]

thank you! there's actually a more complete fix that avoids generating unnecessary code, so I'll close this in favour of #3518