Update regression test quoting for Windows compatibility

The " double quote works when used with cbmc directly on the Windows
`cmd.exe` command line, but not when used in combination with `test.pl`.
So this commit swaps to usage of ' single quotes instead, which does
work with `test.pl` on Windows.

Author: thomasspriggs

regression/cbmc-incr-smt2/nondeterministic-int-assert/control_flow.desc

@@ -1,6 +1,6 @@
 CORE winbug
 control_flow.c
---incremental-smt2-solver "z3 --smt2 -in" --verbosity 10
+--incremental-smt2-solver 'z3 --smt2 -in' --verbosity 10
 Passing problem to incremental SMT2 solving via "z3 --smt2 -in"
 Sending command to SMT2 solver - \(set-option :produce-models true\)
 Sending command to SMT2 solver - \(set-logic QF_UFBV\)

regression/cbmc-incr-smt2/nondeterministic-int-assert/incremental_solver_called.desc

@@ -1,6 +1,6 @@
 CORE winbug
 test.c
---incremental-smt2-solver "z3 --smt2 -in" --verbosity 10
+--incremental-smt2-solver 'z3 --smt2 -in' --verbosity 10
 Passing problem to incremental SMT2 solving via "z3 --smt2 -in"
 Sending command to SMT2 solver - \(set-option :produce-models true\)
 Sending command to SMT2 solver - \(set-logic QF_UFBV\)

regression/cbmc-incr-smt2/nondeterministic-int-assert/trace.desc

@@ -1,6 +1,6 @@
 CORE winbug
 trace.c
---incremental-smt2-solver "z3 --smt2 -in" --trace
+--incremental-smt2-solver 'z3 --smt2 -in' --trace
 Passing problem to incremental SMT2 solving via "z3 --smt2 -in"
 Assert of inequality to 4\.: FAILURE
 Assert of inequality to 2\.: FAILURE

regression/cbmc-incr-smt2/nondeterministic-int-assert/valid_unsat.desc

@@ -1,6 +1,6 @@
 CORE winbug
 valid_unsat.c
---incremental-smt2-solver "z3 --smt2 -in" --verbosity 10
+--incremental-smt2-solver 'z3 --smt2 -in' --verbosity 10
 Passing problem to incremental SMT2 solving via "z3 --smt2 -in"
 Sending command to SMT2 solver - \(check-sat\)
 Solver response - unsat