The fix in commit v3.2.3~3^2 (Fix assertion failure on unmatched foreach
in function, 2015-05-18) broke handling of unmatched non-loop blocks
because it assumed all function blockers removed during error unwinding
were for loops, essentially switching the set of mishandled cases.
The purpose of the loop block push/pop operations is to define a scope
matching the lifetime of the loop function blockers. Since our function
blockers already have the proper lifetime, simply move the push/pop
operations to their constructor/destructor.
Extend the RunCMake.Syntax test with a case covering this.