ST_CurveToLine drops first vertex of a straight curve

[strk]

Passing a straight line to ST_CurveToLine:

CIRCULARSTRING(0 0,1 0,2 0)

Results in a linestring missing first vertex and having a duplicated second vertex:

LINESTRING(1 0,2 0,2 0)

1.5(.9) is _not_ affected, 2.0 and 2.1 are affected.

I guess 2.1.0 could wait for a fix to this. I have a fix locally, which doesn't change any of the existing regression tests results.

See also #2407 which is the context in which I've found this one

[strk]

Fixed with r11745 in trunk (2.2.0), r11746 in 2.1 branch (2.1.0), r11747 in 2.0 branch (2.0.4)